I have six young kids. This attitude is absolutely prevalent (and it's insane). I've been chewed out by a cashier for sending an 8 year old into a store alone. I've had a person run out of a restaurant, panicking, and grab my 2 year old because she was walking too far ahead of me. I've had people tell me it's unsafe to let me 10, 8, and 5-year olds bike together in the park ahead of me while I walk.
Just giving my kids space when I'm nearby, in sight of them has terrified countless onlookers.
No one has actually called CPS on me, thankfully, to my knowledge. But the general atmosphere is absolutely crushing for people who want to try to safely let their kids learn independence.
I was 10 in '72, in a big metropolis. I'd take off on my Stingray bike on all day jaunts all over. The only comments I got were from my mom who made sure I had change to phone home in case I got a flat. I started a 4am paper route on that bike two years later, nobody batted an eye. It was the best of times.