I'd bet that the belief of likelihood of prosecution for a drug crime is about the same as being sued by the RIAA or MPAA for most people. They're aware they could get in trouble, but it's unevenly enforced and unlikely to actually happen to them.

Regardless, I don't think the willful infringers are the most interesting group here. If user generated content really does lead to sites getting shut down in an unreasonable way (which is probably unlikely to actually happen), I think it's those groups that would be leading the charge to a next gen network, not the infringers.