Doesn't explain why they are always near the front though. I get that they need to be a bit wider for people to manoeuvre the kid out of the car seat and in to the pram etc, but not why they need to be right next to the door. This deprives lazy people of a great space meaning they have to illegally use the disabled bay or sneakily park in the drop off/pick up bit.
So you don't have to trudge across a busy car park with a 2 year old, perhaps? Probably in the rain with and with a trolley laden with a weeks worth of food.