Possible unintended consequence: when the RMT advertisers try to friend you, you cannot blacklist them until you have completely declined the friend invite.
As a PS3 player, this is a more than just a little annoying. While I do play on a big screen TV, the screen itself is across the room from where I sit. Since many of the RMT accounts are randomized characters, it is very difficult for me to read their names from where I sit, and then be able to correctly enter them into the "report for advertising" screen.
I was thrilled when SE added the functionality of blacklisting from the chat window, as this made it so much easier for me to stop the constant tells. This doesn't work with the new "friend invite" method, as I have to go decline the invitation first, then blacklist.
Personally, I would be happy for another short-cut option that would report them for advertising, blacklist them, and not be stopped by the friend invite all in one.