There are many MMORPG's that just blanket restrict tells/whispers below a certain level, usually 5-10. unfortunately the RMT's just bot their sock puppets up to the required level and the spam is just as bad. I don't see how a quest would stop them.

I have not used a whitelist in an MMO, but it sounds like a good idea - the current blacklist is a joke, mine remains full and has been for a long time.

That said reporting could be improved, I've just realised this morning in trying to report an RMT that SE have recently broken the default copy command (ctrl+c on a PC) which now brings up the currency window. so now as SE wants an example of the RMT spam message when you report, they just made it even harder to actually offer this proof. I hope there is a copy command I have overlooked, but I'm not going to type verbatim every single spam I want to report.