f1m4rc:
Actually according to wgt, blocking a player does prevent them from being randomly matched with you
Well, if that's what WGT is saying, then it's not working. Many players have complained about being matched with players on their Blocked list. And I've personally had players on my Blocked list get chosen to join one of my AS games when I've clicked the Anyone button to pick up a random player.
One more thing blocking does do, though, is prohibit them from chatting with you in a coin room if you do get matched up with them.