... ive worked warped tour for 2 years, and have gotten backstage passes both times.
I also snuck in one year, and ended up backstage, and needed a pass from someone, so I asked a couple bands, and they gave me their pass from the day before.
its wayy better when you have a pass anyways. you can watch bands much closer, and not have to deal with a bunch of people.
and dont act obnoxious, otherwise youll get kicked out..just act like you are supposed to be there

