If that happened I could just imagine what Yobit has din when it attempted to re-enter Bitcointalk, a lot of inactive members woke up and when all the complaints broke in they are just trying to save Yobit's ass that its a good signature campaign that doesn't promote spam. I could imagine a temporary forum wide sig ban will just make a lot of members inactive and when it will be brought up back again then you will see that these members (or accounts) will be back being active again. You will really see the real members who will stay and won't stay just because of a sig ban.