Blocking hiding boxes and stashes in foundation?

Some players hide their loot into stone/metal foundations in boxes or small stashes.

I can block foundation upgrade from wood with void OnStructureUpgrade, but how to detect the boxes under foundation?

 

That bug seems to be fixed, I cant do it on my test server.
Screenshot

 

Try to hide small stash, it is possible without any bugs.
Next, how to hide boxes and more others you can see in this video:

 

The only way I could recommend it is that when a player upgrades a foundation that is either twig or wood to anything else higher do a vector search for the stash bag, if it detects a bag in a small area (eg 5 metres) then it will decline the upgrade. problem is that if you have something like building grade mod installed and players can use the up command it may skip that check as I don't think that mod would check each foundation.

 

Yes, but need to block also that on the video.

 

sadly, cant watch the rest for now, but maybe someone else will have more ideas.