It would be a spur of the moment decision.
Couldn't agree more. Plus, everybody has a different view on what's considered dangerous. You could find yourself in a situation without realizing the danger.
I once saw a guy beating the crap out of his girlfriend in front of The Wing Dome in Seattle. So, I ran up to him and lied, saying, "Hey man, the cops are coming!" He looked at me with gratitude and said, "sh**t, I'm packin" and took off down the street. I never saw his gun, so he could've been lying, too. But, if I tried to be a bad-ass and rough him up instead of bluffing, who knows what would have happened.