There is a lot of places where you can get away with it even in dense area of the US and Germany. There is some social engineering going on there. If you live

There is a lot of places where you can get away with it even in dense area of the US and Germany. There is some social engineering going on there. If you live in an area where everybody locks his door and don't have a huge problem (like bands of bored teens trying every house, or lots of junkies, ...) the chances are very small that anyone would try to open your door, and if they do, they most likely come prepared. I remember that in my previous flat in the center of London, we left the kitchen window opened for years without even realising it. It would have been trivial to break into our place, but nobody cared. They entered 2 times over the same period at my neighbour place, likely because they saw something they wanted to steal through the window.