My Cricket is serrated, but used as a money clip it's never even been looked at. My plain edged Boye folder with a 2 7/8" blade has only been looked at once as the tray passed by.
I like to carry a couple self addressed stamped cassette mailers so that if some rent-a-cop at a security gate thinks either one is a real threat, I can mail it to myself. Haven't done Europe yet, but I have carried these through three Caribbean trips, two times to Hawaii, once to Alaska and once to Cozumel Mexico. (No, I'm not rich, my wife is a Travel Agency Supervisor for AAA and it's amzing the deals she can get.)
Because my Boye folder is so flat and thin, I can slip it into my wallet and it's never seen. That's also after I've taken out all the credit cards, movie rental cards and other stuff you need at home but not traveling. It's amazing how much your wallet will stretch from all that stuff.
And speaking of stuff. I make sure that I pick the busiest line at the airport detectors, then I make sure that I put my Cricket and Boye in the plate first, and then I pile everything from my pockets on top of them, pens, change holder, memo pad, nail clippers, twezers, etc... . All the while I'm holding on to the plate, patting my pockets and holding up the line. I'm cooperating to the nth degree, smiling and chatting, and they're trying to hurry the nice slightly befuddled old man along. Many times, by the time I've handed them the plate and stepped through the detector, they haven't even looked in it.
Just a little camoflauge and mis-direction.
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All you need is love... a sharp blade and a full clip