It’s not irrational. Knives shouldn’t go any higher than the chest and far from the head and neck areas. Gotta be a Fremen to do that thing,That's actually one of my irrational fears... that at one point I'll have a lapse of brain activity, resulting in me scratching my nose or my forehead or something while still holding a knife in my hand, and stabbing myself in the eye or something.
Knife salute... not going to happen for me...