I'm told the people who ignore all the "Don't do this if you have a psychiatric disorder, numbnuts" warnings that well-intentioned people like Erowid put up, even if instead of HPPD they "merely" end up with shit like a "simple" panic attack, because they are on acid, it lasts for several hours and feels like a year. Who the hell wants that? I can sort of imagine that outcome, but I can't even begin to imagine the living nightmare HPPD must be.
(Edited to add: I'm sure more of our Munchausen lolcows don't claim this one, easy as it would be to fake, because then they would have done something illegal and no longer be "innocent victims.")