Yeah those gigs are weird. Once I had to do sound check with a coule of thousand kids in the room, and they were carrying on "talking" and I could talk to the stage without a talkback mic.
I also lots of thumbs up, right after they pointed at the subs.
They were really happy to be there, something you don't get from normal gigs.
The biggest issues I had was being asked to turn the horn waaaay down, as the loud HF would tend to hurt some of the kids who had a little hearing and it would overload the hearing aids.
They (the people in charge) said they did not care how it sounded quality wise, as long as the bass was really pounding and the lights were flashing alot. If you didn't have pounding bass you would not be hired back!
I always enjoyed doing gigs for them.