There are some basic psychological methods to de-escalating aggressive people. Some of the best bouncers and security (real, not mall cops) never have to lay a finger on people. They form a non-aggressive partnership with the aggressor or give them face saving ways to "win" without any further escalation, and can then lead them down and away from the situation. Of course, being cool and calm enough to do that often comes with knowing that you can physically control and stop that person easily if needed (which comes from skill and training in combatives).
I've heard of this from somewhere...
