A signature ban and a real ban are practically the same thing for many of these members, who are only posting to get paid. So I would certainly have no objections to not allowing them to use their sig space for advertising, at least for a while. Then maybe they'll get the message (if they didn't already with your campaign ban) that they need to seriously improve.
LoyceV has a post or thread on users who get temp bans actively posting again after their bans finished (as I remembered). I think LoyceV has data on this, and things will become clearer if he can provide how many percent of old participants of past rounds of Yobit campaign join CryptoTalk.
From such data, I mean that temp bans don't play huge role on control spammers. They will abandon their accounts during ban period, or leave accounts in hypernation phase, but when something pay high, they will actively come back and make spam posts.
Not a bad idea either. Theymos shocked me when he did that with the Yobit participants last time, but I thought it was reasonable. A lot of those folks had flooded the forum with more garbage than usual and I think they deserved what they got--and the punishment IMO was fair and not overly harsh. Not all of the participants are shitposters, so going by the ones that were banned from Yahoo62278's campaign would be a good guideline on who ought to be held accountable.
It shocked me too, but honestly I felt it is unfair somehow. Spam is spam, burst post is burspost no matter which campaigns users join and wear signatures when they spam or burst post. There are lots of spammers or burst posters who don't wear Yobit signature have not been temp banned.
It seems Yobit mades noise and people focused too much on them and their supporters months ago. Punishments are likely harsher for Yobit participants, but anyway it is the forum managed by theymos (and some others), so they have rights to do anything they want to keep it clean.
He/she/plaguebot may have the same avatar and signature, it's still not me 
