Coding, in my experience, tends to consume a lot of time especially for a kid who is getting into it. I think many of us here can recall the long hours or even all-night coding sessions we did when we were young, learning, and everything about programming was new, exciting, and frustrating at the same time.

When I was young (12-15) I spent a lot of time programming and very little interacting with other people outside of school hours.

The same thing can happen with video games or even reading of course.

Coding outside while running around sounds like a bad idea. But if you meant non-concurrently, then I agree: kids have lots of time, especially if you don't allow them very much screen (TV, play computer) time.

I learned php on a handspring visor with the manual downloaded into a offline browser app while on the playground. Couldn't even run my code until I got home and hotsynced it!