How timely that I happened to find this discussion just two days after taking a domestic U.S. flight. I was returning from New York to Florida, leaving Islip MacArthur airport in suburban Long Island, headed for West Palm Beach. Now, when I go through the airport I try to be efficient about it, and part of that means getting all my metal objects into my hands for deposit into the security baskets, so I don't back up the line digging into my pockets after making the machine beep.
Well, this time I was an idiot: even though I got my change, my Zippo, my space pen, etc. etc. out of my pockets, and put my CoPilot into the basket concealed under a fold of bills, I completely forgot that I had my Myerchin rigging knife in a nylon sheath on my hip, under my shirt. The whole deal, stainless handle and marlinspike. Well, the woman working security reminded me I still was wearing the knife when her wand happened across it, and I was genuinely surprised and embarrassed. She asked that I remove it, she looked at it in her hand, then put it into the basket with my other stuff, checked my belt buckle (the last thing that beeped) and sent me on my way.
Next, though, the woman on the x-ray machine wanted to know about a couple of things in my carry-on knapsack were. One was a Nalgene water bottle filled with water, which she made me drink from (presumably to be assured it was not nitroglycerine) and the other was my Leatherman Wave -- which I also would have put into my checked baggage if I had remembered it at all.
So the CoPilot raised no eyebrows at all, and even the larger Myerchin, marlispike and all, did not cause a hassle.
As far as travel in Japan and Britain...well, I have nothing good to say about either of those places. The morons who run those asylums still perpetuate the lie that if you disarm the LAW-ABIDING, you'll protect them from crime. Fools. They think that banning tiny knives does anything good for society? Let 'em go to hell, then.