Oh for cryin' out loud. Just argue the issues, eh, and skip the, "it's getting windy," nonsense, eh? Otherwise, the impression will be created that the issues cannot be argued.
Now, MJS. My point is that when Clyde says, "Nope, that's wrong," him bad to judge. When you say, "Nope, that's wrong," him good to judge. It seems quite possible to me that you both know what you're talking about.
Pete: one reason to use both hands is that elbows bend. Good committed roundhouse, relaxed arm, block only bicep, attacker says,"ow," fist comes around corner, hits face. This is bad. (The reason for not simply checking the "center," is similar: you're creating a pivot point. Look at Snapping Twig, for the results of shoving the center.)
Another reason: so that you don't have to add in an "and," before slipping the hand-sword to the neck.
Another reason: to maintain consistency with other techniques for relative novices--forward with both hands up, 5 Swords; backwards, Delayed Sword.
Another reason: to teach us to, as I read in "Black Belt," as though it were a big discovery," "use both hands."
Another reason: who said you've got to fully block? step in, slip the handsword from bicep to neck, keep the left up as a check.
Another reason: who said you have to block out? Block DOWN on the arm with both hands.
Another reason: to teach the basic checking system, in which the left is the first, most obvious, check. My favorite version of 5 Swords: both hands up to check their right, ball kick to the gut or groin.
Another reason: to introduce the possibility articulated more-completely in Defying the Storm--lock up the arm/shoulder.
Can all this be countered? Sure, you can stay home and never have some slob throw a punch at you. You can arrange to have your brother drop a Steinway Concert Grand on them, when they appear. All you have to do is to read their mind.
But I will tell y'all right now--I'm not bad at this stuff (tho' assuredly not god's gift to kenpo...that'd be Juan Serrano, the best kenpoist you never heard of in the country...ask Clyde, he hadda spar the monster for Juan's fourth test...ever see anybody do full-out spinning butterfly kicks in sparring, spontaneously, land a couple, keep on going? After getting decked by a much bigger opponent?)--I'm not bad at all, I've had the benefit of wonderful teachers, I'm smart as hell, and Clyde ties me in knots all the time with counters to techniques.
So I don't know what to tell ya...