Comment by fc417fc802

I guess they're probably operating on the assumption that at worst a few short nails stuffed in a small film canister are no worse than the metal handle from a rolling suitcase.

The swab is for common explosives. The canisters are a bit on the small side but I guess could still pose a threat if packed with high explosive and a bit of shrapnel.

The apparent annoyance (or worse) is the part that gets me. The entire process just feels needlessly adversarial. At least they didn't insist on patting you down or emptying out your bag!