That’s nothing, at general admission club (or some festival) shows, people will gather up by the stage for one of the later acts, but totally disengage from the performance to text, read facebook, whatever, while those who are trying to watch the band and enjoy the show stand 5-10 rows deep. First come first serve, but we aren’t talking about people even “at” the show. They suck the energy right out of the moment.
Yup ... and I don’t know the answer to the problem, either.