I was driving today to run some errands, with my wife in the passenger seat. I stopped for her to drop off the laundry, and waited for her with the brake on "hold" without putting the car in P. She comes back and I drive off. About 5 minutes later I noticed that the car was no locked. I know that the car auto-locks after you drive up to a certain speed when you put it in D from P. Does this not work in the situation I described above? I don't know why they don't detect that the car has picked up speed and auto-lock always. Is it just my car or is this how it is supposed to be?