It really doesn't matter to me. If I were them though I would insist on a doctor's statement indicating that as far as they can tell she is a virgin. I know that isn't the best proof, but that is the best I can think of.
She's is stupid. But she has thought it out if it is real (all the conditions).
I mean, as a 19 year old virgin (and very poor college student) I'm getting kinda desperate and I wouldn't mind the money but I'd rather not be a hooker!