Look at the current rally going on in Waco. There are tons people in front of Trump while he's speaking, probably no seats, but anyone can get in there. Tickets would not have been necessary. Think they are only to estimate size of venue they need. On the people in the bleachers behind him.... my take. I remember some of the people associated with the rally were talking to various random people in the very long line... I suspect many of those in the bleachers are handpicked by the rally set up people.