Actually, all they need to do is ban/sue/whatever buyers. I wanna play keyboard lawyer for a sec. If the buyer is from the US (I don't know international law), would that mean SE can bring charges to them? Specifically "Receiving stolen property". If SE gets a rep for taking buyers to court, it may stop buyers from actually buying.

Recing stolen property: "The offense of acquiring goods with the knowledge that they have been stolen, extorted, embezzled, or unlawfully taken in any manner." Keyword there is "knowledge". Buyers know it's not right to buy gil, but they do it anyway, prolly because they think they can get away with it. They may not know it's actually stolen from SE.

Remember kids, you don't own jack when you play this game. Your character, actually belongs to SE. Your mega-awesome gear, that's SE's too. Most importantly, the gil belongs to SE, it is not yours to sell or buy from an RMT.

Reference: http://legal-dictionary.thefreedicti...tolen+Property