Earlier quoted context omitted.
So what happens in winter when I go turn my car on thirty minutes before I leave to make sure it's nice and warm?
Could be a special switch on the fob for that. Could beep every five minutes to remind you. Lots of ways to handle it that would save lives at the cost of only minimal inconvenience.
If you add a special switch, that increases costs. Why should car buyers bear extra expenses for less than 100 deaths a year?
Should we require special bathtub sensors that beep when they detects still water because hundreds of people drown in bathtubs each year?