It'd be a pretty interesting experiment to see unfold, since it's the sort of thing that would probably be picked up by the gaming media. Which, in turn, would cause the reaction to be scrutinised very carefully. Rival MMO's could also potentially exploit the situation for their own game by highlighting that they allow for the use of certain mods, too.

Besides, if they did ban thousands of players then that'd open the door to people asking why they haven't banned the hundreds of players who hang around in Ul'dah on Balmung and Mateus with explicit search info.