I have also read comments from the taxi driver and thought of something today....
I have found it weird that JW would spend not even a full day searching for LS, then assume she's missing. If she's really the "party girl" that people have suggested her to be, wouldn't you think perhaps she was just off with some guy (especially given that she'd been seen with one the night before and that maybe she and JW had broken up?) I'd think that was a possibility, at least, and if so, I would think JW WOULDN'T want to alert her parents to that scenario. I can maybe give his story more credence since he learned that she left her cell at the bar and hadn't gone back to get it, but still not convinced.
However when I read that the taxi driver said that he'd heard that LS had left before, that made me think that maybe JW knows that and perhaps that's why he jumped to the conclusion of her missing so quickly. We don't know if he went over to CR's to inquire about her, but given that someone on here said CR/MB were in a CVS and knew earlier than reported, that she was missing, one can only assume that he did. If so, he seemed to take this pretty seriously. To me, that either points to him already knowing she was gone (as in some involvement) OR he knew she'd done this before. I just do not think that most college guys would assume someone is MISSING and file a police report and call a girl's parents all b/c she left her phone in the bar.
I could be wrong.....perhaps CR was SUCH a bad influence (and why he was hit) OR perhaps he went over to CR's and learned that Lauren had gone to JR's and THAT was more concerning to JW. Maybe JW felt that LS was at harm for having been with these guys. I just feel that if LS hanging with them was that serious of a threat, there would have been more than just one punch to CR's face.....