They could ban players from making accounts where the names are a jarbled mess of vowels and consonants but people like playing Roegadyn characters.

Joking aside, I'm not sure how they'd solve it, they made reporting it super easy, but I know that can get tiresome and doesn't really stop it because they return under a different account. Heck, making gil in the game isn't that hard either, so not like making it easier would solve it, giving 500k gil with jump potions doesn't seem to have killed their market either. I hope they are banning players who buy gil too.

There is the GW2 option of selling gil themselves, but that's also not a good idea here for other reasons, and GW2 seems to have a different economy anyway where it'd be less of an issue.

I guess weird nonsense names can be flagged automatically as suspicious to GM's and investigate, but even then I get the feeling gil seller's would catch on and find a way to use no-nonsense names and then take up legitimate character names. They can also parse strings of shout text but everytime there is a hit for keywords and automatically flag them as suspcious, but then gil sellers can obscure the string to avoid detection logic, I've seen some really creative ones in the past.