Eli5 why is it bad if kids/babies in car seats wear coats


I want to start off with I don’t have kids and don’t ever want kids. I just see the post floating around a lot and don’t understand.

Kids in coats add an extra few inches to the car seat buckle. But if the strap is secured the kid can’t physically move with the coat on. If the car crashes the seat belt will act the same as if the kid wasn’t wearing a coat/the strap was correct… right?

Adults wear heavy coats all the time with seat belts and no one says anything. What’s different with kids?

In: 9

The coat is puffy so the parent will loosen the straps, but then in a crash the puffiness will squish down and the kid can slide out from the loosened straps.