That depends on the location I guess; where I live in Spain kids can basically do whatever. Hell, they come to parties with their parents that last until 8 in the morning. There we do not have the paranoid thing that guys cannot pick up / play with children of others without being called a sex offender either. He is talking about western world, but I am in Cambodia now and here kids seem to be allowed to wander (or boat in floating villages) very far and in cities I saw almost no parents picking up kids from primary school; they all seem to walk away alone.
In the Netherlands, for the parents I know, are also not very restrictive or paranoid, even in cities.
Maybe this is fear induced US/UK stuff mostly? I do not know about the US but the UK parents I know seen weirdly over protective to me as the article states. Not sure that is good for children, especially considering that most kids, if not allowed something, will try to do it anyway or excessively do it when older and/or away from home. Like when relatively young UK guys came to a campground in Amsterdam on their own, we (Dutch) were looking in horror at 17-18 year olds smoking weed, drinking, passing out and vomiting basically 24/7. As my parents told me to try anything, I did not feel the inclination to try a lot and as I did not have to sneak around, I never felt the need to do things in excess when away from home.