"As you may know, one of the most promoted features of MK9 was the balancing on the fly, without patches. For the most part, this has worked, as there have been changes in the past few days such as infinite removal and some move property changes.
However, there is one kink in this, and it's not exactly a tiny one. The updates DO NOT save to your hard drive. When you are disconnected from XBL, the updates do not take effect at all. They are all just stored online. This is a problem for when these updates bring in important changes."
So, as you can probably see, any tournament running Mortal Kombat on Xbox 360 would need all of the console connected to Xbox Live in order to make sure that they are playing the current version of the game. The video below talks more about the issue.