I was updating my old regular builds, some of which are years old, and I got the MOO cheat alert for a number of them. Except, I built them myself and I never use that cheat. Ever. In the entire lifes...
But keep in mind a lot or room built with moveobjects enabled will delete alot of stuff without it on when placing it.
And no I haven't had this alert.
Using MOO myself, I actually don't recommend having it on all the time. Only when building and placing things in build mode. For example a wall lamp on a diagonal wall.