Just because some warning labels seem stupid doesn't mean that all warning labels are useless. I don't want to enable idiots, and there are plenty of tort reforms I'd like to see, but you're making an assumption about personal responsibility here that isn't as simple as you'd like it to be. There are dangers in this world that common sense not only won't warn you about, but may even lead you directly into. Drinking too much water, for example. How many times have you heard health advice along the lines of "drink plenty of water?" Does anyone ever qualify that by saying that too much water can be fatal?
What if someone eating at a restaurant dies because poison somehow wound up in his food? Would it be his own fault for not taking the time to have the food tested for poison before consuming it? He chose to eat that food, after all. Personal responsibility and all that.
I'm all for taking responsibility for my own actions, but I understand that not everything is under my control. I live in a world so full of random chance that I could be killed suddenly right where I'm sitting, unlikely as it may be. Deciding blame is not an easy thing to do. I, for one, do not spend my time searching through medical texts looking for ways to die so that I can avoid them, and I think doing so would generally be unhealthy. So when I stumble into something dangerous that common sense doesn't warn me about, I'd appreciate it if someone knowledgeable told me to stop.
I think that, in general, anyone putting on a contest that involves anything physical at all has a responsibility to make sure it's completely safe by consulting an expert. Personal responsibility means accepting the responsibility when your negligence causes harm to someone else, too, you know.