On 2 separate occasions, I have returned to my code to see that my staff members have made changes without my permission or knowledge, and I do not know who it was.
I have 2 solutions.
The first is a screen that shows when your staff members join your map and when they leave.
The second is a Magnifying glass that only the owner of your code can have, allowing you to see who placed what blocks. It would obviously be discernible from the moderator item.