My suggestion is to add a function to the right click menu in the chat window. The purpose is for the reporting of RMT /tell, aka Gil spammers. While I reference Gil spammers here, this could also apply to all forms of RMT.

When said spam messages are received by a player, they would simply need to right click on the character name of the sender. The right click menu would then pop up, at which time the recipient of the spam message would select the new option, i.e., "Report Gil Spammer". A confirmation box would appear; and upon clicking ok, the offending character's name, the text of the /tell, date & time stamp, and any other pertinent information would automatically be forwarded to the appropriate game admins for review. Additional functionality could be included to automatically add the spammer to the recipients blacklist when sending the report.

RMT damages the game for all players. One of the most effective ways to combat it is to make it simple to report.