Sometimes the grief of the offender is worse than punishment by the courts.
My aunt and uncle had sixteen children, all home at once. They only owned one car and so had to make two trips if they went somewhere together. They never left a child in the car. In fact, the one and only time they forgot was leaving one child at church on the second trip. If they could keep up with sixteen children, this father could have managed to remember one in his care. And I don't care how busy, stressed or absent minded he was. There is NO excuse.
Neither of which does a thing for the poor soul that was locked in the car. Some things can't be fixed or paid for.