[GFischer]

http://en.wikipedia.org/wiki/Hellbanning

"Hellbanning is a practice used by some online community managers for protecting a community against Internet trolls. The practice involves making a user invisible to all other users. From the hellbanned user's perspective, however, they seem to be participating normally in the community. The purpose of hellbanning is to make it impossible for other users to respond to a particular user by rendering their contributions invisible"

No idea whether the editors can un-hellban someone. I guess the best if the user wishes to keep posting to the community is to make a new account.