There are lots of mnemonics people use to remember that their kid is in the back, like putting their briefcase/backpack next to the child, clipping the keyless entry keys to the car seat, running a bright cord from the carseat to the front, etc.

But most of the times these accidents happen, it's due to a change of routine - father taking the kid to daycare instead of mom, an emergency phone call on the way to work causing distraction, etc. It's times when people skip the routine, and make a mistake.

So in the end, criminal punishment ends up punishing people for being human.