There are still kids with unstructured outdoor time, mostly in the rural areas. They're referred to as "free range kids".

I've been aware of my sun sneezing since I was a kid. My dad, an optometrist, said it was because of the proximity of the optic nerve bundle to the sinus nerve bundle. The overstimulated optic nerves stimulate the sinus nerves and caused sneezes.
Being aware of it, I notice it in a lot of people.