Which professionals do you consider least trustworthy? Car salesmen? Politicians? Telemarketers? Bloggers, maybe? Let me suggest a new addition to your list: you simply cannot trust a knife expert with no scars.
This is the consensus view among self-defense instructors: if you are attacked with a knife, you will get cut. You should expect to get cut. Your goal is not so much to avoid getting cut, but to avoid getting killed.
So next time you meet a self-defense expert, look at their arms. Do you see any knife scars? Have they even once tested their theories against a real, razor-sharp blade?
British raconteur and martial artist Chris Crudelli managed to find one Escrima teacher with sufficient courage to test himself—on camera, no less. Here is the footage, from the BBC documentary Kick Ass Miracles:
Yes, he failed the test, and nearly chopped his arm off in the bargain. I am not particularly surprised at this outcome. Nevertheless, I wish we had more self-defense instructors of his caliber, and fewer of the type who are so casually mocking him now.
Do these results prove the man to be a self-deluded idiot? I sure hope not, because if the rare martial artist who actually tests his theories is subsequently labeled delusional, what does that say about everyone else?