There is already a feature to remove a player's shops once he hasn't visited the server for a certain time.
This feature is about finding stale shops, that aren't used by players, even though the owner is still active.

Possible variations:

• Periodically check vs check on command invocation
• Tool for shop owners vs tool for server admins vs both
• Automatically remove vs only notify vs notify and remove after a while
• Unused shop: No trades vs no trades and no edits (no interactions)

Possible implementations:

• Store the timestamp of when the last time someone traded (or interacted) with the shop
• Vs: Use the new history feature (once it becomes available) to check whether someone traded with a shop within the last x days