I agree that the ability to disable the receipt of anonymous messages sent to your account would be a good thing.
I also think it's a shame that we have to consider it for the reasons we are.
This is a game people, try not to abuse it's features it hurts all of us in the end. Not to presume what Murzim would do, but I'm sure the more time you waste of his, the more likely he would be to simply strip certain parts of the game out rather than deal with the headaches that come with it.. or to ban the involved parties rather than deal with them.
Also, the more time spent on issues like this the less time spent on adding more features to the game. So please, if you are one of these anonymous messagers, stop.
'Mario Teaches Typing' <--- just got it for my Tandy