There’s background on this: basically, back in the day, play used to be a matter of “Hey kids, have fun and be back before dinner!” and chores used to be a matter of “Could you bike down to the corner store with this money and buy us some milk?” Things are different now: kids unattended by adults in public places for long periods of time are assumed to be neglected. Police have been called on parents because they trusted their kids to stay safe (and the parents were right), and this triggered a whole “free range parenting” advocacy … er, I wouldn’t say movement, but let’s say discussion.

Is the world more dangerous for unattended kids in public spaces now than it used to be? Not significantly. Our culture has just become a lot more risk-averse, and isn’t very tolerant of people who don’t live the same risk-averse lifestyle, possibly because “free range kids” now stand out, whereas they used to be just “kids”. I’m not even sure risk-averse is the right word, since IMO your kid’s more likely to end up in some sort of serious trouble by using the Internet in their bedroom than by spending the day skateboarding in an empty lot with their friends, and people don’t usually have any problem with the former (neither are really likely to cause harm either way, I’m just saying actual risk isn’t correlated with perceived risk).