A week ago, a woman was charged with leaving her child in the car while she went into a store. Her 11-year-old child. This week, a woman was arrested for allowing her 9-year-old daughter to go to the park alone. Which raises just one question: America, what the heck is wrong with you?

I'm not interested in defending mothers who are under stress or are low-wage workers without a lot of great child-care options. I mean, fine, but these defenses should be unnecessary because what the heck are we doing arresting parents for things that were perfectly normal 30 years ago?

At the age of 9, I walked to school with a group of other 9-year-olds. Or by myself. Across the very busy streets of the Upper West Side, at a time when New York City really was very dangerous. Past housing projects. Around construction sites.

My sister rode the subway to school at that age. My best friend got on the crosstown bus by herself in the first grade. Attrition rate among my classmates and myself: 0.

Leaving an infant in a car is extremely dangerous, and parents should take great care not to do so, including buying something like this.

Leaving an 11-year-old alone in the car is no more dangerous than letting her go to the ladies' room by herself. Infants die in cars because they can't regulate their own body temperature very well, open the doors or windows, or get out of the car. If your 11-year-old doesn't know how to open your car doors or has to be strapped in, then by all means, take them into the store with you. But if you are the parent of a normal, healthy child, then there's no reason that he or she cannot be left by themselves for a few minutes.

Nor is there any reason that a normally intelligent 9-year-old cannot be allowed to play in a busy, safe park by herself. Could something bad happen? Yes, though the risks of accident in a crowded park are pretty limited. But something bad can happen anywhere. The rate of stranger abductions is very low, and it has been very low for a long time. Yet when I ask parents why they can't let their kid out of their sight, stranger abductions generally top the list.

You know what's really dangerous to your child? Getting in a car. It's the leading cause of death among kids ages 5 to 14, followed by cancer and drowning. Stranger abductions are way, way, way, way down on the list. Yet at the same time we've been tethering our children to our knees in an effort to make sure nothing bad ever happens, we've actually slightly increased the number of vehicle miles they travel. Why aren't the cops on that?

You can argue that driving is necessary, but it seems to me that raising independent children is also necessary. Arresting parents who allow any child younger than a college freshman to spend time alone amounts to a legal mandate to keep kids timid and tethered. This should not be an object of public policy.

I'm not saying that parents should take their toddlers into the wilderness and leave them there to hike their way out. What I can't understand is how our society has lost the ability to distinguish between that and letting your pre-teen hang out in the car for a half-hour or spend some time in a nearby park.

As Jessica Grose says, if this had been illegal in 1972, every single mother in America would have been in jail. Yet millions upon millions of us lived to tell the tale.

Megan McArdle is a Bloomberg View columnist who writes on economics, business and public policy.