Would you say it is a stereo type that...?

if woman goes out with a nice guy, you won't be protected but if she goes out with a bad boy, she is?
I'm asking this because the night I went out with a bunch of people, some I was friends with and some were friends of friends. A few of the guys were the bad boy kind. Some guy was was hitting on one of the girls that was with us at the bar and her tough bad boy boy friend didn't do anything, even when the guy grabbed her arm when she tried to walk off. My friend Brian asked him if was going to do anything and he didn't say anything. So I went up to say something to the guy. Me the weak nice guy.

So, do you think it is a stereo type about the nice guy compared to the bad boy?