If it has any items with the 'stealing' warning, it's owned. Only those in an 'unowned' building are potentially safe. (Assume any container respawns unless you KNOW differently. Meaning they don't 'respawn' which is what makes a container 'unsafe' for personal items. 'Safes' remain empty after being looted for the rest of the game, giving the appearance to be safe storage containers for personal loot.
