[Esther]

I tend to keep free-for-all containers behind locked doors to which only those with permission to be in there have the key.

For example, a player house being used as an 'inn&tavern' style restaurant, only the kitchen staff have the key to the kitchen, so even though anyone could open the kitchen cabinets, only the kitchen staff can open the kitchen in the first place. So if you wake up one morning to find that all of your cooking chocolate and seaweed have gone missing, you know it's either one of your staff that stole it, or one of your staff that was careless enough to leave the kitchen door unlocked.