I know that in certain countries like Japan or South Korea: it’s normal to leave the front door unlocked since the probaility of someone breaking in is low since their crime rate isn’t high. I knew a friend of mine who resides in Korea where they even left the car unlocked with the keys inside, can you do either of those things in America?
cctv is not as much of a thing in the us. Largely dependent on bussinesses and not much so far with public cameras. Few places are going to have rates that low but they exist and ones with higher rates still have people that by and large keep the door unlocked. Its mostly a perceived thing really though. Im not sure I would call it safe just because its uncommon. I always thought it was foolish to not utilze something like it but I do tend to use the bolt as its easier to not lock myself out because I have to use a key to lock the door.