IIRC this is because the user commit plagiarism or something against to the forum rules, instead of permanent ban, signature banned is imposed due to some reasons for a particular range of dates, sometimes a month banned to a year or more.
Some of the other reason I know of why a user is banned is if the user is a spammer or a bad poster maker. Admin can ban them for a certain period of time like this quote:
Signature bans cannot prevent user accessing the forum, they even can still post.
True, but they can no longer carry the signature of the scam site. It's good to be part of the prevention solution.
Scams are not moderated AFAIK. That's why those joining such campaigns are negative-tagged and have active flags raised against them.
I know that scam are not moderated and most of those participant have been red tagged.
If I'm not mistaken, some previous yobit signature campaign participant should also be banned from displaying signature just because yobit is a scam exchange. Meanwhile, both site have been proven to be scam, so I think it's a good idea for the admin to take the same action as the yobit participant.
~~~Your friend should be grateful~~~
No, I'm not talking about friends or people I know. He's not a friend of mine and I created this thread to find out how likely it is that other users (if promoting a scam site) are ban like that. However, if the ban is only given due to plagiarism, then it is unlikely that other participant will be banned even if they use a signature from a scam site.