I would completely agree with you on this, but, unfortunately, "willful neglect" is a legal determination, one that can only be ascertained through legal proceedings. That is the case for most cases involving an "intent" element. Anything else, any non-judicial determination of intent, is just your best guess and "gut feeling" and nothing more.
If I wanted to get rid of my child .. in much the same manner as other parents who have murdered their children .. I guess the safest way is to put them in a car seat and leave them in the sun .. and put on a shocked and tearful face for the camera.
To make these determinations is what a trial is for. If you feel comfortable in asserting that no parent would kill their child in this manner, then you can be so comforted. I, on the other hand, am not.
Actually, I think you may be wrong in your understanding of “willful neglect” which requires an element of “knowing and willful” behavior, i.e. some type of intent or knowing disregard of possible outcomes.
This is probably why they dropped the case for lack of evidence. They have a problem showing she “knowingly” left the child in the car. She didn’t “know” because she forgot. How do you prove somewone “knowinglgy” forgot unless you have further evidence and history of other types of neglect and poor parenting.
This is completely different from parents that willfully and intentionally left a child in the car while they shopped, gambled, did drugs or partied, basically using the car as a playpen in leiu of finding and paying for appropriate child care.
Criminalizing stupid is not going to help or protect society. Although it will certainly become a new cause celebre and bureaucratic growth industry.