This suggestion arises out of an ongoing problem with people experiencing having their worlds "reset" by the game after downloading an update... and new information about the cause of this problem.
Apparently, since downloading the updates can get really bogged down (particularly with some slower internet connections), people are prematurely exiting the update process or are simply being kicked out of the update by Microsoft Live (I was kicked twice while downloading the current update).
This causes the game to revert to an earlier version. Thinking they are still OK (i.e. still just in the version they had just before trying to update), they then open their game save... but the game is in an earlier version. This corrupts the save causing all their work to be lost permanently. Then, when they do eventually complete the update and then open their world, they find themselves in a new world with all their builds gone.
This devastation could be prevented if a safety block were inserted so that the game would just refuse to load any world that has already been opened with a more recent version of the game... so adding such a fail safe is my suggestion here. In addition, an appropriate warning should appear upon loading the game whenever an incomplete update status exists cautioning people against attempting to load any of their previous game saves.