Like EvilGinger said, i think there would be a different adventure involved. The most recent one had some monsters from MM2 anyway! - Are we to play Brain Moles, Dung Snakes and
Wolf-in-Sheep's-Clothing's?!
I also believe that you only get goodies if you make other people sign up to the same newsletter. This is a devisive scenario that Wizards also used with MTG players, as i imagine only one person in a group of friends gets the goodies while everyone else just gets bothered by spam.