My new car has a push button start - - to turn the engine on, I just have to push a button (as long as the key is fairly close by, like in my pocket). Within a week or so of having the car, my wife went to the market, came back, and realized she'd left her coupon folder in her shopping cart. She's a coupon ninja, so she was pretty bummed out.
I said, let's rush back and see if we can find it. So we jumped into the car, with me driving. Since she had just been using the car, she still had the keys in her pocket. But it didn't matter, because it was close enough for me to start the ignition.
I drove to the market, and she spotted what she thought was her cart in the cart return. She jumped out of the car. With the keys in her pocket.
Right away, a warning light came on and an alarm started chiming warning me that the key wasn't in the car. I figured the car was just going to turn off right in the middle of the road. So there I was driving after my wife, staying as close as I could without running her over.
(She found the coupon folder.)