My home county of Arlington's Department of Human services has published what it calls "the minimal acceptable standards for the supervision of children developed by professionals in collaboration with the community." According to these guidelines, eight-year old children "Should not be left alone for any period of time. This includes leaving children unattended in cars, playgrounds, and yards." I not only played in my back yard unattended at age eight, but, if I remember correctly, was free to wander around my neighborhood unaccompanied by an adult so long as I came home before dark, and in New York City (Queens) no less. Somehow, I survived unscathed, as did each and every one of my peers.
[By the way, I'm not arguing over whether it's good practice to keep your eight-year-old supervised, I am instead arguing that its absurd to claim that allowing an eight-year-old to play in the yard unsupervised does not meet even a "minimal acceptable standard" for supervising children.]
UPDATE: I learned of this from a mother who was charged with criminal misconduct for leaving her child asleep in a car for five minutes while she ran an errand:
I left my daughter in the car to go into a store for a few minutes. Passerby's called the police. She had fallen asleep and I knew I'd be back in minutes and was unaware this is unlawful [because, as we shall see, it's not]. I was away approximately 5 minutes but the officer wrote a summons for me to appear in court.
Summons: I was charged with a Class 1 Misdemeanor, Contributing to the Delinquency of a Minor. The officer had the discretion not to cite me but he did.
Case Outcome: My case will be dismissed if I complete a parenting class and 50 hours of community service.
VA Law: The VA General Assembly several times considered bills that would prohibit children being left in cars. This bill has not been passed in VA however, it has passed in other states. My lawyer told me in the Commonwealth of Virginia, they lump infractions into basically Misdemeanor or Felony. The trial proceeding determines the outcome. In my case, the section of law I was cited with 18.2.371 is a broad interpretation of rendering a child in need of services, in need of supervision, or abused or neglected. If it involved the temperature of the car too hot/cold then it could have been a more serious charge.
I think it was an abuse of the police officer's authority to have charged the mother with a crime when the Virginia legislature had specifically decided NOT to make the behavior in question a crime. Moreover, states that do have laws banning leaving children in cars usually specify that the child must be left alone for at least ten minutes. So the legislature failed to pass a law banning the action in question, and in jurisdictions that do ban it, the mother would still have been in compliance. Yet the "justice" system still charged her with a crime. Unbelievable.