I think you completely misunderstood what I said. I'm not justifying the "she was asking for it" defense, if you read on I go on to say that from an objective standpoint I think the facts reported are deplorable. The issue is, as is the issue in all of these cases, is what both individuals percieved to be the situation, and what was either verbalized or otherwise communicated. I'm sure that IN THIS KID'S BRAIN (and this is not, in any way, shape or form something I condone or believe should have been the kid's thought process) he thought that he had consent. That belief likely came from some earlier communications or something that led him to believe that she was consenting. Obviously, objectively he should have known that any prior consent or hints at consent go out the window when she is passed out drunk. So I guess it is then up to a prosecutor and a jury if charges would have been filed to determine whether his belief was a reasonable one, which I do not believe it was.
That's the problem with this type of law. Knowing consent is an ambiguous standard, and one that courts have long tried to get a grasp on. Read up on any any SCOTUS criminal procedure case where consent is an issue (consent to search, waiver of rights, etc.). SCOTUS has essentially said that you have to look at the totality of the circumstances to determine if someone is capable of giving knowing consent, which is basically to say that it's impossible to create a bright line rule but rather the issue of consent is taken on a case by case basis. It's a hard standard and it leads to unfair results on both sides of the coin.