I worked at a pizza joint when I was 21. One of the jobs was making sure that the under-21s weren’t helping themselves to the pitchers of beer. This wasn’t my favorite job because you could run into clowns who’d argue about it. Softball teams seemed to attract a few of these.
So one Sunday a couple of bikers came in with their girlfriends. Young girlfriends. They ordered a pitcher and two glasses, and cokes for the girls. They had been sitting in the parlor for awhile when I saw the girls with beer in their glasses. Being a fool I went over and said that if the girls were going to drink beer I’d need to see some IDs. The bikers said “no problem” and took the beer away and that was that. Of all the people I dealt with in this situation they were the most polite.
Anyway my impression is that ‘civilians’ aren’t likely to have much trouble from bikers. If you’re a rival gang, if you’re a competitor in crime, if you treat them with disrespect, then you’re going to have a lot of trouble. But these aren’t like street gangs that intimidate local neighborhoods.