Implement a 'Report RMT spam' option in the chat popup
Then the server counts the number of reports.
When reports go over a certain amount the server checks the log on the reported person.
It will count the number spams such as shouts/whisper for the past number of minutes.
If that person spammed over a set amount, they are autoban/muted or whatever SE does to spammers.

In the long run this will save a lot of man power on SE's part since RMT spammers can be dealt with quickly and will also improve player experience since there should be less RMT spam reaching the players.