Calling this "sexual assault" is just crazy. There was no force, she never told him to stop. This would be thrown out in court without question in any half-way sane country.
The situation described falls within the definition of sexual assault in the United States, at least. I am not a lawyer. Decide for yourself: http://codes.ohio.gov/orc/2907.03
As nice as that sounds, there isn't a shred of truth to it in the real world. Pre-emptively asking a female before making a move will get you shut down every time. You're supposed to read the situation, pick up on signals, and often be a little bit psychic. Show me a female who wants you to explicitly ask permission before every action and I'll show you a liar.
That's not a reason to not do do so.
A process which has no relation whatsoever to that of borrowing a vehicle, I might add.
If you want to go reductio ad absurdum on me, you can twist what I said to imply that I'm suggesting it's fine to go around raping people first and asking questions later, but I trust that a rational reader won't have issues understanding what my actual message was (even if they disagree with it (wrongly)).
I agree, this can hardly be marked as assault. From her account, she barely made an effort to let him know that his advances were unwelcome.
If she doesn't have the ability to stop him and walk away from the situation, which she was perfectly capable of, then maybe she shouldn't be out in the adult world.