You are talking about last 2 weeks, when yobit entered, actually in this matter, mostly negative trust members are joined yobit, and yobit accepted them, that's why yobit and negative trust accounts were banned.
In signature campaigns all negative trust accounts are not working, because they all are scammer.
However If rank is not matter then definitely trust will be matter, we can't trust in member who has negative trust, then doesn't matter that he/she is newbie or Sir. member.
Nope, that wasn't the case, you should understand though, not all red tagged users are scammers. Some are just victims of misunderstanding how the rules work over here, e.g no promotion of Ponzi or projects with scam accusation or no account farming. That's why theymos have say it time without number, "Do not rely on the trust system, always carryout individual research before trading with a green or red tagged individual".
Yobit's signature campaign and their participants were banned because of spam. Although not all participants of the campaign were banned anyways, only those that did get one good report against them for spamming the forum irrespective of their trust scores. Also the campaign ads got banned because it was encouraging spammers through paying them to spam the forum not because of any shady business of theirs that doesn't relate to the forum.