We all know about the idea of a seal, yes? Something which allows anyone to get in, but (hopefully) ensures we know about it if they do?
Well, normally we think of seals as one-time-use gadgets. I mean, obviously, it’s no good if the person can put the seal back together after they break it.
However, what if the threat model doesn’t involve the adversary breaking in while you’re away. What if the threat model is the “adversary” breaking in while you’re in the other room?
In that case, it’s sufficient for there to be an audible warning whenever the potentially undesirable action is taken. The latest post from Barry Wels & the Lockmasters crew illustrates this nicely — a lock with a built-in bell which rings whenever the lock is operated.
This way, whoever’s in charge of the store or bar can tell “by ear” if a crooked employee goes to sneak something from the cash register or liquor cabinet is opened. (After hours, presumably there are other security measures put in place.)