Being on that list is a ticket to hide any member's signature
Exactly! And therefore that would stop incentivizing spammers to spam"No one can know you or Grievance against your decision"
To be discussed. The system could show who marked the user as spammer. And there could be an option for others to unmark him if they disagree or if the post quality improved.Then there could be a formula to decide whether or not to remove the signature rights, just like users can have an overall positive trust if someone trusted left them negative feedback and several others left positive trust later.
At least 6 DT2 members or 3 DT1 members are needed, in order for a user to lose the ability to wear a signature (this way it will be less prone to abuse)
6 and 3 sound too much to me to be honest. But there should be a method to prevent non-spammers to be affected because a single DT user didn't like his post, either by initially requiring more than one tag or by allowing others to untag, as stated above. 
