In my opinion, a threat of, say, a monthly ban will make most if not all of the campaign managers more careful and less promiscuous in the selection of new participants for the signature campaigns they happen to manage. Obviously, the unofficial forum rules should be amended with a special section concerning campaign managers and their responsibilities...
A thread is going to stickied very soon with rules/guidelines for both managers and signature campaigners and punishments for people who run the campaigns very poorly.