my thoughts on these, note i'm not involved in this gig, but applying some common sense . . . .
J* said:
If someone falls and hurts themselves who's responsible?
If you fall and hurt yourself in any other club who's responsible? Was the floor wet with drinks and not promptly cleaned up? were you being an idiot and dancing on a bar stool? etc etc.
There's host reponsibility (reasonable safe environment), there's patron responsibility (don't be a dick), and there's the knowledge of the type of gig you're going to (skydiving carries more risk than walking, but probabaly less than an AKL taxi ride . . .

)
J* said:
If someone gets paint in my drink, is it safe to drink?
If someone accidentally spills ash in your drink is it safe to drink? Kind of. Would you? i hope not, and if you do, i'd probably use that as an intoxication / idiot test.
J* said:
Does that person buy me a new one if not?
Depends on the person really doesn't it? If i accidentally knock over someone's drink (99% of the time having happened the other way round) i always offer to buy them a replacement, but that's because i'm polite. The average twat does not, and in this case i'd suspect no different to any other club in town, roll the dice and pray for boxcars.
I really don't see the difference btw this and any other gig, there's fun to be had, there's some risks, you weigh up the odds and decide if you want to be part of the madness.
Should also be relevant to note this is a USA fad at the moment, and being one of the most ligitious (sp?) countries on this planet i'm guessing it's a kinda low risk environment . . . . ?
my 2c.