There was a chaos in yobit.net signature campaign as far as I can remember but were they banned here? I can't remember.
Has it ever happened that due to spamming, theymos banned any signature?
Good question.
It is not always company advertising some service that should be blamed for spamming in forum, in some cases campaign managers should be temp-banned for accepting and keeping spammers in their campaigns.
They are not only hurting service they are working with them but they are making all other bitcointalk forum members look bad.
I've hired spammers, everyone has had a few.
So you are admitting of hiring spammers in campaigns and you think this is ok

You need to sleep or something, your goal shouldn't be to spin up drama.
Yes I have hired spammers. I've given 2nd chances to someone with a somewhat crap history and even sent a warning to them prior to hiring them. Then you have users you don't know or feel were spammers but they soon show they are and get themselves on the blacklist. I even overseen the yobit campaign and fired hundreds of spammers cleaning this forum up.