For the longest time SE actually was taking RMT sites to court, especially back in FFXI. It's a problem that's hard to deal with. The advertisers are a low cost thing for RMT. They make a new character that used to never leave the opening instance, now I think they have to at least get them to a certain level. You're better off blacklisting or going on busy status because at any given moment there's at least 10 RMT sites advertising, each one with several bots. In the time it takes to ban one, they can make 10 more bots to take its place. It's a hydra. Instead of banning them as they pop up, it's more effective to pursue other methods. The problem is, you just can't eliminate the issue. There's a 1 tell per second limit in place to slow them down. There's the tell level limit. They have a chat filter set to catch spam, which is why RMT advertisements constantly get more convoluted. It's a problem more complex that it seems on the surface level.