I don't think you really can stop them or their behavior. If you're an adult and you still need to be told, hey, don't act like a jerk, being drunk in public is not cool, or don't ride your bike recklessly when you're packed tight with hundreds of other riders, then you probably are never going to hear or seriously consider that message.
I love SJBP. But because it is an open event, you can't stop jerks from participating. And the bigger SJBP gets, the more jerks will show up for it.
The size of the ride is at the point now that unless the overall group decides to turn on bad riders, they will continue to come. The group is too large for the ride organizers or any small group of people to make that difference. But let's be candid: most people who do SJBP aren't interested in policing others, playing that role. I think I'm like the vast majority of SJBP participants: I just want to ride with my friends.
If I were tasked or asked to tell other people to cool it, unless EVERYONE around me were doing the same thing, I'm not interested in that. Everyday life for most people is already too full of conflict and having to deal with shit people, I know I don't want to have to deal with more of it, especially when I just want to ride my bike.
So I hate to say it, but unless the tone of the overall group changes and everyone shouts down the jerks, more of them will continue to show up. And the more of them that show up, the more likely other people will drop out because people come to ride and have fun, not to deal with jerks.
I really hope I am totally wrong and things work out and the jerks tone it down/go away. But I dunno…. So far the cops have been very cool about it all and the jerks have been more annoying than dangerous. But all it takes is one confrontation between jerk and motorist or one insult from jerk to cop and it'll be all over. I don't know that that can be prevented if the number of jerks keep increasing.