Did the US get a free album with the game when preordered?
In Aus if you preorder Mad World SEGA Aus is giving a free album soundtrack of the game. Not sure how well this baiting strategy will work, but I know a few people including myself pre ordered the game just because of the free soundtrack haha.
There is about 1million Wii's sold in Australia. So I wouldn't be too surprised if this offer sells 10-20K copies of the game when it launches.