As far as everybody knows about the rules of tc : "If people are deleted because of a rule violation, they are given one chance to come back. If they are deleted a second time because of rule violations, then they are automatically deleted if they return, no questions asked."
We will see how this proceed..
I dont think it matters if user A is deleted for a reason.. (may be it was a mistake??) User A is deleted secod time.. (another mistake? who knows. 
) .. User A gets deleted for the third time..(again a mistake? )
Well..
I think we have right to ask questions about if there is a general amnesty about the deleted users.
I dont think it really matters if user A comes back despite the fact that "A has been deleted several times because of the forum rules" .. (Of course, there will a problem of trust of the judments about the deletions but we can ignore that.. 
) The question is what about user Bs, or Cs?
Is there any reason why those deleted users should not come back?
We will see
What amnesty? mere speculation on your part! No repeatedly deleted users have come back as far as we are aware - like I say 
. If evidence should exist that a repeatedly deleted user has returned then the rules will be enforced. Hope this puts your mind at rest.
