I'll use MOO to do little things like put two objects on an end table move or a dresser just a bit closer to the end of a bed, and I test the lot without cheats to make sure it's playable and place-able. All my builds are now going to be tagged MOO, even though they don't require MOO to use.
Related: CUSTOM CONTENT.
If you have custom content enabled while you build, the game considers the build Custom Content, even if you used nothing but base game content. If you have it enabled, start building, turn it off and restart, the lot you started will still be considered custom content.
https://thumbs.dreamstime.com/b/zero-tolerance-policy-blue-stamp-white-background-zero-tolerance-policy-blue-stamp-98288911.jpg