|The dot is meant to let you know the door is safely locked.|
If you're in an accident, a locked door will do quite a lot to keep you from being ejected from the vehicle, especially if you're one of those morons who doesn't like to wear seat belts. A locked door will also keep you from falling out of the car, and believe me, I know a little bit about that. When I was 8 years old I was in the back seat with four of my cousins in a car driven my Uncle Floyd. As he took a turn a little too sharply the back door opened, because it wasn't latched properly, and I went flying. After bouncing across the gravel shoulder I rolled about four feet down a hill. While nothing was broken, I was a living, breathing road burn. I always lock my car door, you know, been there, done that, don't want to do it again. I like the safety feature. The asshole beside me this afternoon likes to live dangerously. One of these days he's going to hit a telephone pole a little too hard and he will be catapulted through the air with the greatest of ease, head first into a concrete pavement. At that time it's going to be a little late for him to think "hhmmm, maybe I should have locked that door."