Though we will never know what JM said to Hannah that got her to go with him, she willingly did. That she was inebriated, tired and confused could have contributed to the situation. We also know that JM did make a stop at Temp, pay for two drinks, and after that the description of Hannah was quite different from what we saw of her on tape. Even with the grainy quality, hard to see footage, it's clear she did not need help walking, much less standing. The checker, "Abby" states that she was very drunk and looked like she needed support at about 1:40AM. But still, we can't say for sure, she was slipped anything. Just looks likely to me.
But regardless, I think that given that condition described, she could have dozed off, passed out, or zoned out when she got into the car. Again, we are just presuming that she was offered a ride and that the Corner was where she wanted to go,but we'll never know for sure. Though highly unlikely, IMO, it is possible that she agreed to go out with JM for some recreational sex. Where we draw the line in terms of reasonable doubt at all, is that she did not agree to be left as a corpse where she was. Any injuries, beatings, whatever damages the ME can substantiate from the autopsy are pretty clearly inflicted on her.
But without anything to connect JM to where Hannah was found, to doing harm, there is a difficulty in proving in a court that she did go off willingly for whatever reason with JM. Lots of drunk girls get picked up by guys and go off doing things they would not have done in their right minds, or maybe they would have.
The ride story has some credence, given that she was on her way somewhere in the area of the Corner which LE pretty much has established from her texts and calls with people. LE seems to be sure enough to say she was at the Mall due to getting lost and they have said they have a lot of texts from her phone. So running into JM and a ride offer would have been like godsend to her. Also, with no purse and just planning to stay around the corner, tight pants on, she may not have brought her UVA ID or any wallet with money or cards. She would not have needed them if she were staying right in the area where she lived and was partying. If that was the case, she couldn't just get a ride with a cab without some hassle. I also suspect her cell phone batttery died, as she was texting away and then last text at 1:06 AM?
The essential things in this case now come down to what evidence could place JM where Hannah was found and any to show he did her harm. Can't prove much of anything as to why she went with him. At best, in terms, of charges, given her condition as reported, he was taking advantage and the "Abduction with Intent to Defile" could fit, but yes, it is possible she wanted to out and "party" with him upon pick up.