I make a habit of always pressing the lock button on the driver door. If the car is on, or the key inside, it will give you a warning beep. If you do this unconcsiously every time you leave the car, you're going to reduce the chances of accidentally killing your whole family, etc.

The guy in the article was 85 and forgot to take the key out of his ICE vehicle.

And finally, it's been my experience that the TCH runs on the electric when it's not moving. Are we saying the ICE will kick in to recharge the battery if it gets low? Cuz if not, there's nothing to worry about.