I always found BHX staff in T2 to be far more thorough than any of STN, LTN or LCY, so I was surprised to hear about the programme. They, IMX, would pick up on anything at all.
By comparison, given the rules (I don't think it would have been an actual threat to the plane) I was surprised to see an AMS screener the other week allow a pair of folding scissors through after inspecting them closely.