I do not know how they got the car open but they were putting away some electronic gizmos as I got back. Maybe the little boy did not understand what they wanted him to do or perhaps nobody thought of it.
I believe if you know where you can buy a device that will open any modern car. No idea how it works as every time you press the button it generates a different code. The place where I take my car for service had one as they opened it by remote with their thingy. If you are thinking of nicking a car though you still have to get over the steering lock which I think is still mechanical.