You could go the unlocked route if you wanted to swap that idea for a CCTV camera as well if you think it would be an issue, but I am not sure what level of concern you have. 

They swap them out and take them off-site (home, presumably) to clean.

The seller then swaps cash of their own with the note in the exchange account. 

You're just swapping one debt for another.

Perhaps you forgot to swap out a 9V in the smoke detector after the last moveout, or perhaps that pesky drain pan went missing.

There are also lock system to swap out the core easily.

Yesterday I was swapping out a dishwasher for a coupe nice college girls when I happened to look over at the desk in the living room.

It became a nightmare trying to do a simple swap. 

Rekeying is super easy as well, just use the control key and swap out the tumbler.  

This would only work for those who have the room to build something with a garage on their new construction and have the capability to swap the structures classification (old being the ADU and new being the SFR).