Sure, but as far as I know, there is no way to know when a cell was last updated. (And that doesn't take into account that some cells my have been reformated in some way regardless of a change in data.) Since AB has come out in bits and pieces, we could decide on a particular World and anyone who hasn't updated since that world will be removed.

We might want to exempt people on the far end, since they may just not have gotten through all the levels yet--it would take a while to play through all of them and get three star scores.