I know the trend has been for helicopter parenting in the US, but outside of America, allowing your child to play free of supervision is very much the norm in many places.
Fair disclosure: I was a latchkey kid. My mother allowed me to go out, all day, riding my bike with my friends, playing in the park, and generally getting into hijinks she was totally not aware of (yay youth). And she allowed this all in a time when the crime rate was much higher than it is today.
I find this story enraging. My mother is not a criminal, and neither is this woman, who has now been jailed and had her child taken into state's custody. I get that some parents may disapprove of this mother's decision. And that's fine. But I'd hope, as a society, we'd agree that this is a gross overreach. We've let a fear based upon no statistical backing rob a mother of her freedom, her child, and very possibly her livelihood, and given that the mother is a low income worker, the chance that she will have a robust legal defense is very low unless this story gains enough traction to get her some benefactors.