And I think your approach tends to set a very, very low bar for our expectations of men.
Here's the primary difference: you see agreeing to go back to the guy's room as implied consent, that what happens after is the fault of the victim for doing it. I'm saying that no matter what the girl does, even if she ::gasp:: goes back to the guy's room (which, the person in this particular assault did because that's where the bathroom was located), if she says no, that means no.
And the primary difference between me and the alleged rapist in this case, is that when she says she doesn't want to have sex, I don't force her to have sex, no matter what her actions were leading up to it.
Your solution is not prevention. It's defense/risk reduction. Prevention means finding ways to not have men raping women in the first place. That's prevention.