I always get a kick out of buying a bag of peanuts and seeing "Warning: bag contains nuts" or something of the sort. The funniest disclaimers to me will always be the ones that are blatantly obvious statements that for some reason have to be made in our litigious society.
I'm the guy that, guaranteed, will always trip over the 'wet floor' sign. I've never slipped on a wet floor when that sign is in place, but I swear I've tripped over a wet floor sign in every store I frequent.
I live near Chicago, Illinois, so every couple of weeks my friends and I take the metra train downtown. In winter, it's common to see signs saying 'watch for falling ice'. Now, it has to be obvious to anyone who reads that that noone is ever going to see the ice coming. Maybe someone that isn't the guy getting hit might see it, but never the 'target' of the ice. They just have to put that sign there to let people know that ice might fall so that they can't be slapped with a lawsuit.
The whole funny disclaimer phenomenon is a result of so many people being quick to sue over their own stupidity. Case in point the famous McDonald's Coffee incident causing the 'contents may be hot' warning. Unless you ordered a frappuccino (cold coffee, essentially) from Starbucks, wouldn't you expect coffee to be hot?