Let me tell you a story
In November 2002 Mrs SSK and I attended an event in London, and bought a dozen crackers to bring home. Since we were travelling on service tickets and the plane was full, we weren't sure to get on so we couldn't check our bags at the desk and had to carry them to the gate (the liquids rule makes that kind of thing impossible nowadays).
I had a big tin trunk with the conference documentation so I was directed towards the outsize scanner while the Mrs was in the regular queue. By the time I emerged she was still stuck at her scanner so I went across to see what was up.
They had identified, inside the box of crackers, one which contained a miniature pair of nail scissors. So they opened the case, removed the box of crackers, opened said box and were in the process of passing each one individually through the scanner (while the queue behind was getting longer and longer ...)
Eventually they found the one containing the scissors and confiscated it. They gave us back the other 11 little explosive devices to repack into the case.
I kid you not.