Well rapists, for one - which is kind of the point of banning it, no?
I would imagine it's difficult to fake being unconscious while someone is having sex on you :( I expect they are drugged, and even if they are drugged voluntarily and agree to "whatever you want", that's not really consent. Plus it's pretty depressing. Mind you if I was an unwilling porn star I'd probably prefer to be drugged so I wasn't aware of what was going on... makes you sick really to think about it.