I am also tired of cleaning out my blacklist, but I don't think this is the appropriate solution, nor can I imagine SE instituting this "feature"---they seem to want to do everything to insure that new players feel welcome in the game.

Personally, I would rather that they separate the blacklist into two lists, the current blacklist which would be used for its original function (real players who are annoying) and a new "rmtlist" which could be used for gilspammers. The rmtlist could be kept on the server and players would not need to manage it. In addition, adding a character to this list would server to inform SE that it is a (potential) gilspammer and they could begin investigating. I doubt they would institute automatically preventing a character from sending tells if more than X players added the name to the rmtlist, but personally I would want that too.