Numerous vehicles are equipped with an automatic door locking and unlocking feature. The purpose of this feature is to automatically unlock a door when someone with the vehicle's key attempts to open the door, without having to press any buttons. This feature is designed to make it easier to open a door when carrying groceries, other objects, and even children.

Similarly, the feature is supposed to lock the vehicle's doors when the person holding the vehicle's keys walks away from the vehicle.

Many of these systems advertise and state in owner's manuals that the vehicles are designed to not lock when the keys are inside the vehicle.

Again, this feature makes it easier to use the vehicle while attending to children, because you can place a purse inside the vehicle, buckle in the children, close the rear door, then open the driver's door in order to operate the vehicle.