One of my friends has a fancy new Lexus. It is so slick, you don’t even need to use the key for anything. You can push the button on the key fob to lock or unlock the doors, but just standing near the car with the key fob thing in your pocket unlocks the doors.
And then when you sit down, the car senses the fob thing in your pocket, and you only have to push a button to start the engine.
But then on the other hand, since the key isn’t in the ignition, you don’t have to turn it off and remove it to turn off the car – there’s another button to push to turn it off.
So the first time he drove it somewhere, he forgot to turn it off. He got there, got out, pushed the button on the fob to lock the door, went into his friend’s house for an hour, and when he went back out, discovered his car was still quietly idling where he’d left it!