I'd love to see some progress on RMT getting booted, I really would. Also, you are thinking, which is great. These particular suggestions might be a little off, though. I mean for one, /busy status doesn't just block tells. You also won't have much luck doing some other stuff. :P
Sending tells to the RMT, which sometimes satisfying, is also ineffective because of what people said here. Honestly, I don't know if any of them even ever see the game client... probably just manipulated through other programs.

Also, I believe those randomized tags at the end of the /tells are not to identify an agent, but are actually randomized garbage. It's at the end of the tell so that those ads can easily avoid one of the simplest ways to catch them, i.e. looking for large numbers of character-for-character identical /tells. They make each one just different enough to skip such easy detection. The entire ad is crafted to avoid filters, nothing is a mistake (except, perhaps, the awful English XD).