Locking keys inside the car is becoming more of a rarity in modern cars. For example, its almost impossible to do so in my old 97 BMW. If you push the door lock button down with the door open and shut the door, it simply unlocks itself. It can only be locked with the key from the outside or the fob with the door shut. I can't even lock the keys in the truck as the lock incorporates a push button that can only be double locked with the key or the fob with the trunk shut. I must believe more modern cars are incorporating this 14 year old technology. Probably worth the time to test your current ride and see if it has an idiot resistant door lock system.