There are a ton of blocked phrases and whenever SE blocks or flags something, they change how they send the tells. The best way to do it is what WoW does. Every message sent in game has a report feature by right clicking their name in chat. When you report a person it puts them on a temporary black list for yourself. If enough people click report for that person, that person is locked out of posting publically and sending tells to people not on their friends list or guild. That user can also be flagged without someone having to fill out a GM report. SE is trying too hard to combat against RMT messages when they should allow the community to help them. The report feature can also be used against spammers and annoying people in /shout.