I totally agree with most of the others as I personally witnessed about a dozen similar incidents over the years, even at airports such as CDG or VIE. Someone even told me that he recently flew with a hunting knife, he had forgotten to remove from his backpack, from Europe to Cambodia via BKK without anyone noticing it, until they discovered it at BKK security on the return trip. As you can imagine he was quite surprised!

so much about efficient airport security! its an illusion!