With the serious response from theymos on Yobit campaign, I thought that we might have new unofficial rule on campaigns the potentially cause spamming in the forum:
(1) Participants will get different temp bans: depend on total bad reports on their works during specific period (7 days, for instance), and percentage of good (exact) reports on their posts.
(2) Temp ban on signatures of those companies: 60 days (for Yobit), but the period of signature temp ban might be discussed and should have 3 or 4 levels, like what we have with the forum account's temp ban: 7 days, 14 days, 30 days, and last one is perm ban.
(3) Temp ban of signature on campaign managers whom run spamming campaigns and keep running them after get warnings from admin, staffs, DT members. It means they won't be able to advertise their campaign management roles via their signatures.