The nice thing about dwarf tossing, not that it's a giant social problem anywhere, is that no one thinks it's associated with disease, and if you thought it was associated with injury—of which there is no evidence—you could pass laws requiring the use of a helmet.
From a Q&A with Alvin E. Roth on Repugnant Markets and How They Get That Way, in today's Harvard Business School's Working Knowledge.
More on repugnant markets:
Repugnant is different from, say, disgusting. There are no laws against eating cockroaches in California, because nobody wants to eat cockroaches. The law of supply and demand takes care of that. But the reason there's a law against eating horse meat in California is because some people would like to eat horse meat, and others think that they're doing something repugnant.
But seriously: The Q&A contains flashes of insight re the biases that lead to the criminalization of prostitution and gay marriage -- and there's a PDF with the whole study, too.