Well thats someone with absolute faith in their instructor. There are a lot of folk who think their instructors are these great infailible people... but lets face it, even a great master is only human. I wouldnt let my instructor do that to me, and I have a great deal of faith in his ability.
What do you say to something like that.. most martial artists know of all kinds stupid things like this sword demo that are actual taught techniques. ie.. walking barefoot on the sword edge, picking up a pot of burning coal to brand your arms, putting your head through concrete blocks. punch this brick, let me hit you with a sledge.. The list goes on. Most of these practitioners will come up with some esoteric mumbo to try and justify the technique. But then again, the very next ninja to try and mug me in an alley may very well have wooden armor for me to punch through.