Just an anecdote; I flew an aircraft into a (French) airport and while in town bought a set of 6 steak knives. Put the bag on the conveyor going back to my aircraft and the officer turned towards me as my false knee pinged the machine. Behind her I could see the 6 knives filling the screen of the scanner. She then just lifted my bag of knives from the belt without turning around and handed it to me. I walked out onto the apron carrying my precious cargo of knives.