As communities try to do a better job preventing and limiting abuse, harassment, etc, one common approach has been to put together a committee to hear reports and investigate problems (example). For a community that exists in isolation, my understanding is that there aren't really open legal questions: they can take action up to and including banning as needed. Where this gets tricky, though, is with coordination between groups.

In the contra dance community, for example, there are hundreds of independently organized dances. I once compared this to a pizza-and-subs model, where if you walk into any independent pizza shop, at least in New England, you'll find the same menu, same food, same prices, same service, possibly even the same furniture. They aren't part of a chain that tells them what they have to do to be a pizza place, but they get most of the same benefits in a less organized way. This informal system has some really nice aspects, with high independence and low overhead, but it makes coordination hard.

For example, say someone harms others in one dance community, eventually gets banned, then moves to another city and starts dancing there. They show up already knowing how to dance well, which gives them a bunch of social capital right away, and they're probably able to start their cycle over again quickly. Or someone dances in two adjacent communities, and gets banned in one of them. You'd like the organizations to be able to share information, but figuring out how to do this without opening themselves up to slander/libel is tricky.

In a group I follow someone recently posted that they were thinking about hiring a lawyer to ask some questions around this, and were looking for a write-up of questions. Here's the list of questions I posted there in response:

• My organization has heard first hand reports about someone's behavior. Can we share any of this with other organizations?

• My organization has banned someone. Can we share that fact? Can we share why we decided to ban them without outing victims?

• Is there a distinction between sharing with other organizations and sharing publicly?

• In collecting reports about problem behavior is there anything we need to be aware of around people having a right not to be tracked?

• Do these vary by state?

I have a rough sense of American slander/libel law from reading discussions online, but it would be really useful to get solid well-explained answers to these sorts of questions. I both want groups to be able to coordinate and to be fully on the right side of the law. If this person's effort to get legal advice doesn't pan out I might try to organize something similar.