It's inconvenient. Someone might need to come in at night. A relative, or a neighbor in a jam. You want to be helpful to them.

That is a sort of social fabric I've never known. If I want someone to come in, I hand him an extra set of keys. I probably couldn't even sleep if I knew that someone could come in at will.

And of course, people didn't bash a door in, they used lockpicks, it was a more elegant time. Or at least that was the perception.

Interesting. But at the same time, open doors might tempt people who don't know how to lockpick. Not trying to be argumentative, it's just so foreign to me that it's almost unbelievable.