But then a new thief is spontaneously generated by greed, stupidity or "because it seemed funny", "this person has so many gold bars, surely they won't care abo

But then a new thief is spontaneously generated by greed, stupidity or "because it seemed funny", "this person has so many gold bars, surely they won't care about me taking one" and even "it was out there, unwatched, unlocked, thought it was fine to take one". And you will never know who. Maybe you put all the obvious thugs and hooligans in jail, only for some otherwise kindly old grandma to steal some bars because of the thrill of it. Or a thief from another city in passing. In other places around the world those things are controlled by close-knit communities where being seen stealing would spread the word like wildfire and ruin the thief's reputation (or end up in a beating), not because people is purer and immune to sin or idiocy. It's not pessimistic nor paranoid to lock your door. All it takes is one bad apple, even if it's one in a million.