There is a saying: "The locks in the past were also beautiful, and so were the keys. People will understand if you lock them up. " What does this mean?

In the past, locks were not mainly used for theft prevention. So the locks and keys are beautiful, not as heavy as today's locks. In the past, locks were just a reminder to others, and moral people would know that they couldn't take them when they saw them. There are fewer and fewer people with morality now. So I think this sentence means that people nowadays are not as simple as before.