How does pitching skill affect your zone?

[greymule]

I just finished seven games in an 18-and-under tournament in which I didn't see more than a dozen walks the entire weekend. My strike zone was smaller than the book zone, especially since calling a "letter-high" strike would have ignited the crowd. Some of those pitchers would get 2 strikes and then throw one 2 inches outside and another 2 inches inside—pitches the batters thumbed their noses at—just to set up their 2-2 pitch.

Even with a zone that tight, several pitchers threw shutouts with zero walks.

No, I do not call the same strike zone in rec, where pitches 2 inches off the plate or under the armpits are definitely strikes.