Man that sucks for the mother and son. The father will have to live with this forever, it has already killed him, he just does not know it.

As for "How it can Happen" think abut this, 75% of car seats for infants are installed wrong, it takes 5 mins to get it in correctly. Parents can not take 5 mins to get it right.
In a nut shell as a society we have become lazy and stupid[&:]