How would you convince a person not to use violence /asp/?

Some points I try to remember when I talk people down (bouncer):

-Establishing boundaries early on is really important. If people sense you'll give way on the little stuff, that goes a long way towards convincing them they can verbally/physically harass you without consequence.

-Remember your goal and work systematically towards it. Proving you're wittier than a hobo drug addict provides no lasting gratification, just walk away and let society discriminate him into oblivion. That's the middle class way.

-For every person I meet who genuinely intends violence, there are ten who are attention whoring and basically just want to feel important. If you have ten minutes to play Dr. Phil, you can diffuse the whole thing. Having said that, it also tends to encourage repeat behaviour, so you have a carrot stick kind of balancing act gong on.

I realise this topic is stretching the 'alternative sports' label a bit, but it's a theme that permeates martial arts as a whole. Hit me with your de-escalation wisdom!