Ross,
I appreciate that you thought of me when posting this. And I can certainly see how the thought of if I get hit in the arm now, it won't hurt so much could help a kid struggling w/ fear.
Nevertheless...
He simply turns toward the catcher and the balls deflect off the guard.
That's doing more than adding confidence; it's getting something that he might not (sounds like DID not) actually get as much of before using the guard. Does Biggio wear one too?
He puts both toes on the batter's box chalk
Did he do this as often before the arm guard? (Doesn't sound it.)
His walk totals have also gone up dramatically because the pitchers apparently are very uncomfortable with him hanging over the plate.
This implies that he is gaining an advantage from the device because he has altered his strategy.
I can see what you're saying Ross about doing something to gain confidence. And if he were a kid susceptible to bailing out and this device - tho he may not even get HIT on it - gives him the confidence to stay in there, then I'm all for it. But if he's altering his tactics to take advantage of it - i.e. leaning out over the plate to distract the pitcher's concentration and/or getting more walks by letting pitches hit the device - then I see a big difference. One merely gives confidence by offering a sense of additional security. The other is actually gaining from it (more balls than strikes due to being able to stand closer).
My 2 cents.