If you create group threads that link/tag out to the public and the thread gets member replies/posts/content that non-group members then hide/mute? Yeah, it could (at least based on what I know so far) result in a member getting hammered for a group thread (that allowed public access) and that ban would (based on what I have learned) not only keep the offending/muted/hidden member off of the mains, but out of every group too (for the system generated, automatic, non-moderator set duration of the ban)