The thing is a lot of us would intervene without giving it a second thought, but when it goes wrong or you are labelled the aggressor, where does that leave you?
Many years ago I drove past a lass being hit by her boyfriend, not a slap but a full-on assault.
I stopped the car, jumped out, intervened, he took a swing at me, I blocked it and hit him knocking him into the road, he got hit by a car
All of a sudden I was the aggressor.
Another occasion I waded in, a couple of idiots got seriously hurt, luckily there were enough witnesses on my side, so nothing came of it.
It could have been a whole lot worse if I hadn't intervened though.... decisions, decisions.