I have not read the article but am worried that legislation would be beyond daft:
I have 4 DC 13,12,10,8
I treat them according to their maturity and ability to follow direction/act sensibly in a crisis, not their age alone.
In my opinion being able to independentky walk to places, ride a bike, stay home alone for appropriate periods, boil a kettle, cook a meal are all important life skills that need to be developed....gradually
as such my children all can cross roads alone, and come home from school, the youngest one is not proficient enough on her bike to ride alone...but will be able to ride to the small local park by the summer I think. The oldest and middle are able to cook a simple meal, the second child is careless and a little devil may care...skills under development, the middle 2 can make tea/hot chocolate safely , all can use a toaster and handle a knife for chopping. The oldest has no sense of direction so navigating to new places needs practice, the second is great at directions and can easily follow them as can the third, 4th not tested.
Oldest 2 can be left for a couple of hours, 3rd child hates being alone but can be left with someone else, youngest only left with sibs for a quick trip to corner shop etc.
it would be daft to legislate for only "being left alone" what about the context? What about available back up, what about plans for emergencies?
In our local paper yesterday a 4 year old at home with her mother...mother had accident, was unconscious, child phoned for ambulance. Technically and factually worse and more dangerous situation than just being home alone...child did the right thing.
Legislation won't make people train their children for independence...just give a random cut off point where leaving happens