Towards the end of System's headlining set, Darron asked the crowd to "give it up for metallica! they're in the house tonight!" I had already known that, since Lars was hanging out at the programming boards in the middle of the area floor. I was lucky enough to go up and say hi to him, but I didnt wanna bother his experience. He was having a fun time playing air drums and guitar, and singing along to all of System's songs.