Luchtzak
I was stopped at NCL England the other day trying to board with a nailclipper with a 4.5 cm nailfile attached. They said snap off the nailfile, or forfeit the clipper. No Problem !!
However, I reckon if I was planning to do mischief on the aircraft, I would have went for one of the hundreds of lethal glass bottles happily carried on by the passengers, or the gallons of imflammable liquid contained therin.