I've seen the clip, yes. I'm pretty sure I was watching the race, but from the bottom of the hill (I was marshaling I think). The "tester" is someone I first raced with in 1987 so I've been racing with him for a while, and we talked at length about the crash and also about how the guards worked.
What I realized after looking at his wounds, listening his feedback, etc, is that the guards only protect about 1" around the guard. After that the skin either moves (if on hip, ankle, or other bony area) or the flesh around it squishes down (thigh etc). So he had some road rash with holes of "good skin" in the middle and road rash where the guard/skin moved a bit and allowed stuff to scrape (like a bony ankle).
This means that to be effective for real (virtually no road rash) you'd have to resemble an inside-out golf ball, with dots every 3" or so. Either that or you'd need larger size guards, like a BMX or motocrosser. Maybe combined with something else (dual layer lycra w/outer layer cordura?) it'd be much more effective but I think it's missing something.