# Use of strobes as risk to audience?



## jneveaux

Just wondering if any of you have dealt with an issue raised by my director when I suggested use of strobe (flashing) lights as a transitional device for a scene that is supposed to depict a rapid and unrealistic series of events. She said, "Are you nuts? We can't do that! There might be epileptics in the audience and we'd cause them to have a seizure."
I recognize that there is such a thing as "photosensitive epilepsy". See Epilepsy Foundation-Photosensitivity and Seizures. However, I have used strobes occasionally in other shows and have seen them used many more times for theatre and music productions. (I never had, nor am I aware that any of the other strobe users caused any adverse reactions in the audience.) Were they all "nuts"?
Have any of you considered this as a concern and if so, how did you deal with it? If you didn't find it to be a prohibition on strobe use, did you take any other steps to warn of or limit exposure?
Thanks in advance for your comments.


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## David Ashton

After 40 years of using strobes in discos and theatre with zero incidents I feel the "risk" is neglible, however in the interests of your clients a clear warning sign is a sensible initiative.


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## soundlight

Warning signs should be placed at the door that say "Strobe lights will be used during tonight's performance" or something along those lines. Same thing for haze, same thing for cigarette smoke (even from those fake herbal cigarettes), same thing for pyro. I see these signs at most concerts that I go to, as well as most theatre and dance productions that use these effects.

Anyone who is affected by them will still be able to sue the living *&$% out of you if they want to, because we Americans think we can sue for anything that's entirely our fault (seriously, people, grow up, you aren't entitled to damages for your own mishaps).


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## Esoteric

You MUST post warning signs.

But, the chances you will hit the exact frequency that sets off a seizure are little to none. In addition from what I understand to set off one, the effect has to either be an actual strobe or the light must be pointed directly at the person (for example a very rapid S4 chase would not do it).

Mike


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## headcrab

I heard that one "seizure frequency" is 4.5Hz.


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## Sony

Warning Signs must be posted! If an epileptic walks into your show with the warning signs posted then they are taking their own risks, THEY CANNOT SUE YOU. You gave them fair and proper warning and they decided to disregard the warning and risk their own safety. Most epileptics are aware that a lot of productions have strobes and they choose not to go since no one WANTS to have a seizure. 

At all of the theatres that I work at there are placards posted at the entrance of the theatre warning about smoke and strobe effects. It says something like this "Sensitivity Warning: smoke and strobe effects are used in this production." It's written in plain white on black Block Text in plain english so there is NO argument that they couldn't read it because it was in some weird font or some horrible color scheme.

You should have no issues as long as you post warnings.


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## epimetheus

As others had said, warning signs are a must. Clear phrasing with block text. "Strobe lights and atmospheric effects will be used during tonight's performance." I think that was the phrasing last time I saw such signs.


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## Van

As the other have stated, warning signs *must* be posted. The same hold true for Pryo, Gunshots, Smoking, Haze, Fog, etc. 


headcrab said:


> I heard that one "seizure frequency" is 4.5Hz.


 
The typical frequency for a strobe induced seizure is 8 flashes per second or aproximately 8Hz or faster these are the frecquencies at which brainwaves are actually modulating < though I believe Theta waves start at around 12 - 14 Hz but they are not the seizure freqs>. Not as well known is the fact that certain epileptics can have seizures induced by extremely loud noises, or extremely fast visual stimulus such as ...... Hmmm I'm thinking the way the Movie "Natural Born Killers" was shot with lots of camera movement, pans, cuts, close-up, back -off that sort of thing.


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## gafftapegreenia

As has been said, you MUST post warning signs.

Make them look professional! 
SIGN BUILDER 2.0 - INDUSTRIAL SIGNAGE


Derek, is this an appropriate use of the Warning header, or is Notice more appropriate?


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## theatre4jc

When I was in college our theatre would not only post signs out front but also included a tag onto the fire announcement in the pre-show.


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## NickJones

Yes, some venues play "Welcome to (Insert venue name here) patrons please be advised that this show will include strobe & pyrotechnic effects"


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## JD

Signs and announcements are nice, and advisable. In 30 years of lighting, I have never seen it happen but have heard that it does.


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## kiwitechgirl

Only a very small percentage of epileptics are actually photo sensitive anyway (5% IIRC), and they tend to be aware of it. I've had a couple of people ask me if I can tell them where the strobe happens in the show, and I've been able to say "it's after this actor says this line so listen out for it" and have never had a problem. As others have said, put up clear and obvious warning notices and you are OK.


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## FatherMurphy

I worked in college with a girl who was epileptic, but wasn't aware of the strobe effect. While working a run of "Christmas Carol", she finally mentioned that she was going home each night and having minor seizures. The strobe thing was explained to her, she was reassigned to be elsewhere during the strobing, and the seizures cleared up. It does happen.

Also, strobe-type warning beacons on machinery are set to flash at slow rates for seizure reasons, as well as power conservation. This was a major discussion point for railroad and teamster union negotiations in the 1950's.


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## jneveaux

thanks to all for the quick responses and thoughtful comments.


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## zac850

Sony said:


> If an epileptic walks into your show with the warning signs posted then they are taking their own risks, THEY CANNOT SUE YOU.



Anyone can sue anyone else if they want to, they might even win if they get a sympathetic jury (odds are the theater/school would choose to settle out of court as it would be cheeper and a good way to avoid bad press).

However, lots of shows have strobes and cover themselves with a program note and a clearly visible sign in the lobby. Occasionally it is also in the preshow announcement, not a bad idea just for the added 'safety precaution'.

Way back in 8th grade I was in a talent show and the flashing lights apparently set a girl in the audience into an epileptic seizure. I was acting in the show, so I don't know the particulars, but it did happen. She came out of the seizure, and we went on with the show. It does (and can) happen.


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## Raktor

soundlight said:


> (even from those fake herbal cigarettes)



God I hate them.


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## wakkoroti

The frequency we are held to avoid is between 4hz - 24hz.


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## JD

Just "Disney" it up with the signs like everyone says. As for lawsuits, we all remember the woman who sued McDonalds because she spilled hot coffee on herself. (And won!) Anybody can and will sue for any reason, and sometimes they win. Until crazy judges stop such cases in their tracks, we are all at danger of getting sued even if we never get out of bed! 

What we have to try and balance is to take all "reasonable" precautions, and hope for the best.


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## jneveaux

I hope we take reasonable precautions to be as safe as we can and to act with due care for the sake of our audience and participants. If we reduce ourselves to doing things just so we won't "get sued" then we are doing it for cynical reasons. Remember, getting sued and being liable are not the same.


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## FMEng

jneveaux said:


> Remember, getting sued and being liable are not the same.



That's true, but the costs of defending yourself cannot be overlooked either. Many times, even a shaky case pays off for the plaintiff because it is cheaper to settle than to go to court. Therefore, you do have to take reasonable precautions even if it seems a bit silly.


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## Dionysus

Different things trigger different people. Often multiple flashing colours are required for some epileptics.

Many shows use strobes and other forms of aggressive quickly flashing lights, it's just the way things are. As long as you post proper signs, it's all good.


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## kmontagne

Here is a take from somebody who has experienced seizures. Very often the precipitating factors are not well known. My seizures stemmed from a large subdural hematoma last summer. As a result of this and the subsequent surgeries I began experiencing partial seizures -- affecting speech, hand or facial muscles -- instead of the more widespread tonic clonic type. Mine was only a temporary condition but I had about 300+ seizures over the course of 7 weeks. I will still be taking anti-convulsant medication for the next year or so.

The cause of mine is thought to be from the blood touching the brain. It is such an irritant that seizures are very common. During my treatment I underwent numerous EEGs. During these they tried to induce a seizure while I was awake and while I was sleeping. One of the techniques they used was to vary the rate of a strobe. They typically continued a particular rate for 20 seconds or more. They tried the strobe both when I had my eyes open and when they were closed. They never were able to induce one via the strobes.

A fairly small percentage of people with epilespy are photosensitive. Of the estimated 2 million people in the US with epilepsy only 3-5% are. The triggering frequencies tend to be in the 5-30 flashes per seconds. They typically are told to avoid frequencies greater than 3 per second. Other factors include % of field of vision and color. More information can be found here Shedding Light on Photosensitivity, One of Epilepsy’s Most Complex Conditions : Epilepsy.com/Professionals. The web site Epilepsy and seizure information for patients and health professionals | epilepsy.com is full of information.

Sometimes people experience an "aura" -- a distinctive feeling that can come in many forms. For some people these auras give them time to prepare for a seizure. Often the most dangerous aspect of a seizure is the potential for serious injury if the person loses control of their motor functions. I do not take any particular personal precautions related to strobes. If I experience an aura as a precursor I will look away and more than likely kill the strobe. I agree posting at the entrance to the venue is vital. Additionally, I tend to limit the duration of higher frequency strobes that encompass a large portion of the visible area to no more than 20 seconds.


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## renegadeblack

I did a concert show once and was strobing the LED houselights and someone blew chunks. It happens.


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## wolfman005

This topic has been covered before as far as theaters go, but I am wondering if I need to post warning about strobes when I DJ for Homecomings and Proms. I don't post warnings about fog/haze. Should I post about them as well? I was thinking that when going to a dance, most people know that there will be flashy lights, but I'm not sure if that would keep me safe on the legal side. 

I do realize this forum is for theater, but the DJ forum I'm a member of have a "if it looks cool do it" attitude and I'd like a professional opinion. 

Thanks for your time! -Aaron


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## Les

wolfman005 said:


> This topic has been covered before as far as theaters go, but I am wondering if I need to post warning about strobes when I DJ for Homecomings and Proms. I don't post warnings about fog/haze. Should I post about them as well? I was thinking that when going to a dance, most people know that there will be flashy lights, but I'm not sure if that would keep me safe on the legal side.
> 
> I do realize this forum is for theater, but the DJ forum I'm a member of have a "if it looks cool do it" attitude and I'd like a professional opinion.
> 
> Thanks for your time! -Aaron



Though you may feel that you are stating the obvious, I absolutely feel that you should post advisories to "flashing lights and fog effects" at your events since they can carry the same risks as theatrical effects, and the participants are often the same. It definitely can't hurt anything to be extra cautious. Some people may have breathing problems, so I would mention the fog since you'd be making a sign anyway.

As for theatrical shows, if I had epilepsy triggered by strobe effects and was not warned of the use of the effects and subsequently experienced a seizure as a result, I would definitely be upset and I might even pursue legal recourse if my damages justified it. We have to be sensitive to the fact that some people have legitimate health conditions that can be negatively impacted as a result of some effects we use, so we must exercise due diligence in making sure those attendees are properly warned. I don't feel like this is in the same class as the infamous "hot coffee" lawsuits. Coffee is inherently hot, but one can not assume that every stage production will use strobe effects.


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## bdkdesigns

I've been told, by a dancer who was photosensitive, that most strobe lights don't flash fast enough to trigger a seizure. We debated this long and hard and even brought in lawyers to consult with because she was adamant on having strobes in her solo dance piece. Now, we had the "high end" American DJ strobe. However, we eventually had her sign a legal agreement protecting everyone involved from liability (which even then could be iffy) if something were to happen and still went ahead with standard operating procedure by putting up signs at each door and at the box office. 

Bottom line is that even if someone produces verifiable evidence that everything will be ok or if "I've done it a thousand times without an issue", it's never a bad idea to be safe and post warnings anyways. Somebody could in theory get so concerned about that strobe going off and how it is about to cause them a seizure that they could have a panic attack which could in theory trigger a seizure....or panic attacks could be bad enough in their own right and could cause hospitalization. If I use a strobe light, even if it is one flash every three seconds with other lights up too, I'll post that warning just in case. Each case is different and while it was ok for her, it might not be for the next person. It's just like the old coughing syndrome that seems to plague audiences. Once one person coughs, suddenly 8 people do it, even though they didn't really need to but felt as though they did.

It's just never a bad idea to at least make your audience aware that something like that exists, even if you think that it should be obvious that a dance has flashy lights or somebody goes through extreme measures to make sure they can have a strobe in a piece.


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## Wood4321

JD said:


> Just "Disney" it up with the signs like everyone says. As for lawsuits, we all remember the woman who sued McDonalds because she spilled hot coffee on herself. (And won!) Anybody can and will sue for any reason, and sometimes they win. Until crazy judges stop such cases in their tracks, we are all at danger of getting sued even if we never get out of bed!
> 
> What we have to try and balance is to take all "reasonable" precautions, and hope for the best.



I really hate the coffee analogy.
Please look up the facts about that story, Link to the facts of the case. The woman deserved every penny she received.
The coffee was just short of boiling, to keep customers from coming back for refills. She received 3rd degree burns, and required skin grafts to repair the damage. She also asked them to just pay her medical bills, and they declined. (the medical bills were substantially less than what she won in the lawsuit.)


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## wolfman005

My apologies for opening an old thread. I made a new thread and then after I posted it I went to my other tab which had this thread I found and saw that my new thread was tacked onto the old thread.Why did this happen?


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## derekleffew

wolfman005 said:


> ... Why did this happen?


A human moderator moved/merged the post.

In general, the community prefers that posts be attached to an existing thread rather than starting a brand new one covering the same/similar topic. Keeps things tidier, and makes it easier when searching later. We don't mind a necropost, provided it advances the discussion.


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## Les

wolfman005 said:


> My apologies for opening an old thread. I made a new thread and then after I posted it I went to my other tab which had this thread I found and saw that my new thread was tacked onto the old thread.Why did this happen?



Because it is of little value (and often confusing) to have two threads discussing the same thing. Many forums look down upon necroposting, but we welcome consolidating and/or reusing old threads as long as the question/addition is pertinent.

_Posted simultaneously with Derek._


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## variable

I take them seriously. The chance of a strobe light setting you off are little, but if you're like my wife and bright lights bother you, a single strobe flash can trigger you. We were watching the premier of Defiance and the editors inserted a bunch of single frame white frames (this is a big no-no that got past SciFi channels censors), she was down for the next two days. There are a million alternatives to high intensity strobe lights, IMO.


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## flyweed

agree with pretty much everything said so far. We use alot of strobe, haze, fog, and pyro in our facility, and the occassional lazer. We feel being "proactive" is the best way. We post signs at the entrance, we insert a line in the program, and it is in the preshow announce as well. That way we feel we are fully covered, should an "incident" occur.


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## Pie4Weebl

It's funny to me that I always see signs warning of fog/strobes/nudity at theatre, but never at concerts...


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## wolfman005

Do you think this would cover me if I did something as simple as this? Please note that when I say dance on the sign, I am talking about high school Homecomings and Proms. Also, what would you do if the school admins don't want you to put up a sign like this? They scare easy and I worry that if they see something like this they will freak out and ask me to cut the lighting down to par cans.


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## kicknargel

Hijack: A theme park I contract at is converting the tea cups ride for Halloween. They are completely blacking out the ride, with the only lighting coming from a strobe. They are calling it "Hurl." I suspect they're right about that. You can bet they're putting up warning signs.


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## wolfman005

Ok one last question for ya. If someone did start having a seizure, what do you do? Anything besides the obvious call 911 and make sure they are sitting/laying down so they don't fall and hit their heads?


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## sk8rsdad

The first aid procedure for a seizure does not start with calling 911. A single event is not considered a medical emergency. Make sure the person is safe from harm and take note of the time. If the seizure persists for 5 minutes or recurs then call an ambulance. Otherwise just keep them safe.

http://www.epilepsyfoundation.org/aboutepilepsy/firstaid/

Hopefully your facility already has procedures in place that are reviewed and practiced regularly, and some or all of your front of house staff has first aid training.


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## TheaterEd

wolfman005 said:


> Do you think this would cover me if I did something as simple as this? Please note that when I say dance on the sign, I am talking about high school Homecomings and Proms. Also, what would you do if the school admins don't want you to put up a sign like this? They scare easy and I worry that if they see something like this they will freak out and ask me to cut the lighting down to par cans.



As a school employee, I feel like your sign would freak them out and they may ask you to cut your effects. I would make the same sign, only without the exclamation points and the image. A simple "Attention Laser, Strobe, and Fog effects will be used during tonight's dance." Use a simple font and laminate it so it looks more official. I would also consider including your logo on the sign so that you are advertising at the same time.


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## Darkmagi

I know this is an old thread. I found this information on a BBC site it particularly pertains to staff and audience members and covers a few good guidelines. Including warnings, strobe position, flash rate and more. 




BBC - Strobe Lighting - myRisks Information

Safety Guideline to strobe lighting used as a visual effect for entertainment performances.


bit.ly


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## Dan Fischer

We use strobes all the time as well as flicker/ color change from moving lights. We post it in large writing in the program and also mention the use of strobes and atmospherics in our pre-show announcement with our "in case of emergency' stuff.


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## Chris Cotter

jneveaux said:


> Just wondering if any of you have dealt with an issue raised by my director when I suggested use of strobe (flashing) lights as a transitional device for a scene that is supposed to depict a rapid and unrealistic series of events. She said, "Are you nuts? We can't do that! There might be epileptics in the audience and we'd cause them to have a seizure."
> I recognize that there is such a thing as "photosensitive epilepsy". See Epilepsy Foundation-Photosensitivity and Seizures. However, I have used strobes occasionally in other shows and have seen them used many more times for theatre and music productions. (I never had, nor am I aware that any of the other strobe users caused any adverse reactions in the audience.) Were they all "nuts"?
> Have any of you considered this as a concern and if so, how did you deal with it? If you didn't find it to be a prohibition on strobe use, did you take any other steps to warn of or limit exposure?
> Thanks in advance for your comments.


Hi In 1983 I was the light tech for a nightclub in Chattanooga Tennessee and I worked there about 7 years total time. Part of which I ran Lights on the weekends. We had a big dance floor with 4 large strobes all connected to a strobe control box. It could do simultanious flash or sequence the 4 strobes. I often used simultanious flash mode so I would get a brighter flash. I was always told to not run any sequence or pulses averaging 14 pulses per second as it was an epilepsy risk. I never had even one problem with anybody getting ill or otherwise whenever I used them for a 30 second max period and avoiding 14 flashes a second.
Chris


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## FMEng

So 13 or 15 pps is supposedly OK? I doubt the human body is that predictable or precise.


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## Marco Giampa

jneveaux said:


> Just wondering if any of you have dealt with an issue raised by my director when I suggested use of strobe (flashing) lights as a transitional device for a scene that is supposed to depict a rapid and unrealistic series of events. She said, "Are you nuts? We can't do that! There might be epileptics in the audience and we'd cause them to have a seizure."
> I recognize that there is such a thing as "photosensitive epilepsy". See Epilepsy Foundation-Photosensitivity and Seizures. However, I have used strobes occasionally in other shows and have seen them used many more times for theatre and music productions. (I never had, nor am I aware that any of the other strobe users caused any adverse reactions in the audience.) Were they all "nuts"?
> Have any of you considered this as a concern and if so, how did you deal with it? If you didn't find it to be a prohibition on strobe use, did you take any other steps to warn of or limit exposure?
> Thanks in advance for your comments.



I use the same thing in a show afew years back when a characto had to "jump through a mirror". There isnt any real risk. If using conventional blinders there is no real problem. Led stuff likke GLP JDC-1 and Atomics if strobing might be abit sketchy. Usuallu when purchasing tickets online you can put in a popup that says stuff like adult themes, flashing lights etc


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## Jay Ashworth

Sidebar: We mention Hot Coffee up above.

Here are the actual facts of the Stella Liebeck case, which might make you not use it as an example of frivolous lawsuits.

Or, as This Is True's Randy Cassingham points out... not:








Stella Liebeck's Case: What Really Happened - True Stella Awards

May it Please the Court: I know quite well that not all of lawsuits are frivolous abuse of the American Justice System. Many cases indeed involve real issues, real injuries, and deserve real compensation. And some don’t. That’s why I stress that you should read the cases before you judge. How...



stellaawards.com


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## Chris Cotter

FMEng said:


> So 13 or 15 pps is supposedly OK? I doubt the human body is that predictable or precise.


It has been researched. Check for yourself. I also said to avoid frequency around 14 pps not especially 14. I would say 10 and 18 pps to give some leeway.


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## TimMc

Jay Ashworth said:


> Sidebar: We mention Hot Coffee up above.
> 
> Here are the actual facts of the Stella Liebeck case, which might make you not use it as an example of frivolous lawsuits.
> 
> Or, as This Is True's Randy Cassingham points out... not:
> 
> 
> 
> 
> 
> 
> 
> 
> Stella Liebeck's Case: What Really Happened - True Stella Awards
> 
> May it Please the Court: I know quite well that not all of lawsuits are frivolous abuse of the American Justice System. Many cases indeed involve real issues, real injuries, and deserve real compensation. And some don’t. That’s why I stress that you should read the cases before you judge. How...
> 
> 
> 
> stellaawards.com


Cassingham is no better than 'the other side' because he gets to cherry-pick his "facts" in a rebuttal that cannot be answered by the plaintiff. I did a little thermometer checking and found that none of the coffee brewing systems used at a "major corporate/banquet hotel" held coffee at the temperatures mentioned. My highly rated (by coffee snobs) home brewer brews at 190 degrees F, but the highest hold temp is 160 degrees F. Ultimately the question was "should Ms Liebeck have reasonably expected that the coffee would cause 3rd degree burns over her genital area? The answer to that question was "no."

Further, Mr Cassingham posits that Ms Liebeck's case was frivilous because McDonalds used a coffee-industry promoted holding temp; there is no evidence that McDonalds performed their own test regarding the *safety* of dispensing near-boiling beverages to drive-thru customers. Mr Cassingham is very much a 'blame the victim' advocate. The Court found that McDonald's was 80% liable for Liebeck's injuries and McDonalds then settled before final disposition. Why? Because those other injured customers could have made The Hamburger Clown look bad if their injuries were known to a jury.

That there are 24m cups of coffee served for every severe injury is of little comfort to those who *are* injured. That's like saying "well, we can cut corners on rigging because there hasn't been a human death due to a rigging failure in the last couple of years."


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