This is an interesting theory and got me to thinking, since we have explored every other possible scenario, due to the lack of facts....
What if Lauren was in no shape to say "no".. And JR was there all along or came by and all three guys "had there way with her" so to speak. I have heard of this happening with an intoxicated girl at frat party and even with a girl in a group of jocks at a party, when I was in high school.. Often the girls are too embarassed or can't remember enough to report this type of thing, so the guys who are also usually drunk/high feel empowered or safe in "risking it". But what if in this case LS died either from something she had taken, alcohol posioning, her heart condition, or even because one of them got to rough with her... Then they came up with their story together: one of them, perhaps the best at lying agreed to be the last to see her and the one who is the worst at lying decided to just go with memory loss... and they have all stuck to the story because all of them would be implicated if she were found....
Now all of this is a whole lot of supposition, what ifs... etc. Just another thought to add to the many others we have talked about.
My mind has gone there before. It's difficult to not speculate when there aren't more facts forthcoming. It's such a hateful thing to think, but as you said, it has happened. I don't blame LS at all for hanging out with guys she considered friends. A lot of young women do exactly that. But maybe they took advantage of that. It's possible. There are certain types of guys who feel entitled, it seems ...
I've lately thought that LS never made it to CR/MB's at all ... that she disappeared in the gravel lot. That also means that all three (two if CR truly doesn't remember) are lying. Would an OD alone compel them to do that? It's been debated here, along with everything else. IDK. It might if they supplied drugs, etc., but I do wonder about MB. If he wasn't involved in that way, is he just protecting a friend?
Regardless, there appears to be something that's binding them to a code of silence ...