The sort of people described in the OP are the 'ragers we all are concerned about. There's simply no telling what such a person is capable of, if he/she is prepared to be so "off" like that. Scofflaw? Psychopath? Who knows. Disregard of risks and danger ... disregard of civility ... disregard of the law ... zero qualms over lashing out at people ... Wouldn't take much for such a person to be doing the calculus of risk-reward and to actually blow sideways in such a situation, via a full-on attack, or pulling out weaponry. All because the person feels affronted by someone daring to hold them accountable (or even take an interest in what they're doing). You never know.
I'm fully prepared to put a person down, hard, if assaulted. I'm unwilling to ever be the "aggressor" insofar as the law is concerned. And that generally includes letting such abusive scofflaws continue on their karma wheels as they see fit, so long as people aren't directly attacked. But, that's me.