Since I've posted some of my Roller Derby memories in older threads, I won't repeat them here. But as Skipper mentioned, I do remember hearing that Charlie O'Connell (team captain of the SF Bay Bombers) and one of his "arch enemies" (name escapes me right now) owned or partially owned an interest in one of the local bars (again I can't remember the name, but I think it was Irish) and often met and had drinks there, especially on the Sundays after a match.
Another tidbit regarding the SF Bay Bombers that I recall is before Joan Weston joined the team in 1965, Ann Calvello maintained the Women's Captain on The Bombers until traded for Joanie. So the Women's team hero (Ann) became the enemy and was forever to be known as "banana-nose". Also one of her signature gimmicks about that time would be to dye her hair a different color every week(?), or at least whenever her team came back to The City. Anyway long-story-short, my sister and I talked to all of roller derby stars every week, and most of them finally ended up admitting that 99% of the fights during the match were for show, and that most, if not all, of the players were friends or at least friendly in real life.