Before airbags, no one left their baby in their car because, distracted or not, they saw their baby as they were exiting their car.
WTF... you are talking about kids old enough to sit in the front seat. The issue is babies in baby car seats who are not able to unlock and open a door when they get hot.
I did not miss one thing.
In the old days, my mother’s arm was the seat belt - remember when mothers stopped short and their arms would shoot out to prevent kids from heading into the dash?!