In this case, drivers approach the open spot they want with their car, get out and then, while standing nearby, press buttons on a key fob to signal to the car can go ahead and park on its own. (fortune.com)
If you lose keys, you're out of luck, as only way in is with push button on key fob. (carsdesk.com)
And the door and trunk lock and unlock buttons on the key fob come in handy when approaching the locked car with arms full of packages. (articles.orlandosentinel.com)