Doing such a thing could get you arrested, it's called Brandishing, or it could get you killed if you do that to the wrong person. He was not involved with the dispute and it had not gotten to lethal force. He had no business sticking his katana in their dispute. I carry a sidearm everywhere, I would never, draw it, let alone point it at someone that was not threatening grevious bodily harm or death to someone. An argument or fist fight is not cause for lethal force. Had that been me in the argument, that kid would be one dead samurai, with two jacketed hollow points in his chest.