Just about all of these websites/companies are hosted in places where pursuing legal action against them is nearly impossible. If it were as simple as threatening legal action, the problem would have been solved years ago. Thus we hang our hat on the developers to find creative solutions to stop what the lawyers can't. The other option not being talked about here is to allow purchase of gil directly from the game with real money. When that is done, the RMT can't win because they can't produce at a lower rate than the company can and they eventually will give up. This, however, has the negative effect of inflation that must, some how, be countered via the ingame economy.
