I went to a gig by Ministry of Wolves. One of the members is Alexander Hacke from Einstürzende Neubauten, he's not a small guy. During a quiet part of a song you could hear a guy talking in the crowd. Whilst still playing the guitar Alex got off the stage, walked over to the guy and told him to STFU and calmly walked back. For most of the rest of the show he just stared at the guy in the crowd, almost daring him to talk again.