There weren't any riots. I was expecting a riot to break out if they PA didn't get fixed in a few minutes. They did start a few fires in the GA section, but they were all put out almost immediately. They had all the necessary equipment ready in case a riot did break out. There were a LOT of cops and a helicopter circling the place in case of an emergency.
Oh I left out the best part. During the break between Muse and RATM, everyone in the coliseum had to do something to entertain themselves. Well we were a big stadium, so obviously we all spent a good 10 minutes sending the wave back and forth around the reserved seating section