They obviously prefer to err on the side of caution. I mean, nobody has yet heard of an airplane being hijacked with a potato peeler, corkscrew, or cartridge keyring, but who wants to be first? Not them, that’s for sure.
The common sense should be exercised on the part of airline travellers, by sticking anything which a security checkpoint person might conceivably construe as remotely dangerous into checked baggage or leaving it at home, unless one wants to get into protracted discussions with security checkpoint people or their supervisors. (People who think they know the rules and plan to insist should keep in mind that in general they have a flight to catch but the security people don’t.)
(Incidentally, here in the EU, pocket knives with blades of up to 6 cm in length are now OK in cabin baggage, and I’ve successfully taken a Swiss army knife through airport security multiple times. I really wonder what that potato peeler is doing on that tree! Also, you’re allowed one cigarette lighter or package of matches if you’re carrying it on your person as opposed to in your cabin baggage, so unless people have excess lighters I wonder why these are getting confiscated at all.)
