I'm not talking about jab resets, but simply jabbing them at higher percents before they hit the ground to tech. But in any situation, yeah, Falcon can SDI up; but he has to be conscious of that before doing it: you can't react to something as fast as jab. Moreover, I'll mix it up further with a double jab which tends to net me a regrab. It's not frame-tight at all, but it does work. Everything in this game has some degree of fallibility: even fox u-throw u-air gets mitigated by SDI. We're not playing perfectly, and we're not playing against perfect opponents. The thought is more that one can construct scenarios where these weaknesses are irrelevant because the opponent couldn't properly react to it: that's the core of a mindgame.
I can't say with certainty, but I think the video Eddy posted isn't quite the same thing: Green Sheik was knocked down from f-tilt and missed the tech. Blue Sheik therefore shields next to Green Sheik to allow for a shield grab on the standing or attack animations, and intending to wavedash OOS to catch any roll options. Green Sheik did the standing animation into utilt, which Blue sheik reacted poorly to: you can see him drop his shield before getting hit, meaning it probably went for the shield grab. The Fake CC therefore comes from the down throw input, based on how Blue Sheik opted not to pummel at all (Sheiks that pummel tend to do so at any opportunity). Blue Sheik realized that something was off because he wasn't throwing, and THEN went for the regrab.
I feel as though it's different because the utilt is defensively used rather than offensively used, and therefore the options (and thus, the leeway for reaction) given to the receiver are inherently greater than those of the utilter.
So yeah, CC—be it true or fake—tends to beat out utilt, but there certainly would be situations where the opponent wouldn't be CCing in a techchase that this would be applicable: perhaps with jab or jump or f-tilt, what have you. That could certainly take hold if a spacie player loses faith in get-up shine as a defensive maneuver (by Sheik baiting it out and punishing it). It's good to get feedback, though, 'cause I was pretty enamored by this before and didn't perceive the clear weakness to CC it had.