Well this thread got weird.
I guess to me I don't understand why, if there is no key in the car, or NEAR the car, the car wouldn't auto-lock. I understand the quirks of the passenger door being open, or the trunk, but after 30s of no key being anywhere near the car, wouldn't it assume it's good to lock itself?
For me, I think the problem is when I get out of the car, I walk right towards my home (I park on a city street). The car door probably doesn't fully close until I'm 5ft away or so, thus it doesn't lock. I just don't understand the logic of that. The key isn't near the car, the doors are closed. Lock the car! The idea that I need to stand next to my car for a second and THEN go inside tells me the feature is flawed. Someone mentioned it in this thread, if you have to change your natural habits of 'walking away' from a car so that 'walk away lock' works... then it's not a good design.