From the start I've thought that she may not have had a lot of close friends, or at least none on this trip. All of the comments I've seen thus far seem to have come from acquaintances. Good friends would've been looking out for her and wouldn't have let her go off on her own like this. It seemed odd from the beginning that nobody noticed that she was missing until she failed to show up for the plane.
I thought so too. I was assuming she had a roommate who would have noticed she didn't come back to the hotel for the night. I've nothing about that.