Some pubs are more public than other pubs.
Their operators need to generate invite codes. If someone causes problems, the pub operator can unfollow that feed. If a pub doesn't deal with its spam problem, then other people can unfollow that pub.
Those who generate or tolerate spam will likely find themselves pushed out towards the edge of the social graph. That's up to human choice, of course, but that's how I've been operating so far.
the plan is to implement user-invites, where you can create and give out an invite code personally, and when they join there would be an "audit trail" (this could have degrees of privacy, too) tieing them back to you.
some discussions