The big unasked question: How many PETN or other explosives have been intercepted by this new procedure compared to the number of passengers screened.
Answer may be none but who really knows. PETN explosives can be the size of an aspirin and blow a hole in the fuselage. They probably would not be detectable in a scanner.
We never hear of the successes only failures.
But let me pose this to you. If terrorists wanted to get a bomb on a plane, any plane, it could be done without someone gong through screening.