The radio station put her up to it.
The really difficult part about this is that most people don't know that drinking too much water can be fatal. Everyone thinks it's harmless fun, where the worst that can happen is that you might wet yourself.
So it's difficult to think of an analogy, because most things that are dangerous are fairly obviously dangerous. But let's say I run one of those NASCAR rides at the race track where you get into the car and it jostles around and shows moving pictures of the track like you're sitting in the driver's seat of a NASCAR race car. Doesn't SEEM dangerous--thousands of people do it all the time, but it can cause seizures in some people. If you're running that ride and you don't warn me that it can cause seizures, you're going to be on the hook for damages that I might suffer if I have a seizure. It's just the cost of doing business--when people get hurt, you pay.
I would say the same thing applies here. Just because she did this voluntarily doesn't let the radio station off the hook. It's still their stunt.
And how would that sign help you if you read it? Do you know that you're susceptible to seizures?
I mean, if you don't know, then the sign does you no good at all, does it?
If you DO know that you're susceptible to seizures, wouldn't common sense tell you not to get on that ride? Shouldn't you be aware of what might cause a seizure? Isn't it in YOUR best interest to find out what might cause a seizure?
That's called personal responsibility. No sign necessary.