I get alot of flak because I don't believe she left her phone there--but here's why: Apparently, CR knew she was missing by the next morning, when he was asking people around 5N if they had seen a small blonde girl.
We don't know how many people were texting about that in the morning, but CR was out and about, going to CVS, etc. If he was going around asking, he was probably also texting people, too.
If someone had her phone and was playing tricks on her to get her in trouble, mainly posting pics and texting about her being w. CR, the person who took her phone would probably high tail it to Kilroys and put it back.
The phone was discovered when JW kept calling it and this was in the afternoon, IIRC. Anyone could have brought it in starting at opening time
and no one would really notice. People have to realize Kilroys is not a classy bar where someone runs up to a new arrival and takes their order. Just the opposite! Around opening time, they would probably just wait for a customer to get their own drink from the bar.
Say you had been playing tricks on Lauren, first sending pics and texts all around, then keeping her phone from her and getting her all riled up and anxious to get it back pronto. Then, you find out you may have triggered her disappearance after she wouldn't stop looking for it even when she was in no condition to. Yes, you would want to get rid of that phone, especially if only a select few knew you had it. You would need to drop it off at Kilroys.
IMO. either CR dropped it back off, or someone in the HT and roomies group, ZO, ZC, DR, or even JRs out-of-town guests could have done this.
IMO, she could have lost the phone during the altercation at SW.