It would be hard to actually get evidence that they are doing RMT. None of the listings say anything about real money, so for all we know they are doing it for gil(they aren't but there's no proof). Ultimately, we wouldn't have the RMTers if people weren't buying. Banning the RMTers doesn't do anything because they have backup accounts. If we could ban those buying, though...that would have more of an impact, imo.