I've had an almost perfect record leaving from US airports and crossing back into the US. Despite my appearance and suspicious real name, I haven't ever had a problem or been stopped by security. There was one trip with a weird international route that had a security-related delay for me, but that was actually instigated by me deliberately: I wanted to tell US customs to warn another US customs stop at a different airport that I would be zigzagging through Canada and to explain to them preemptively why I was crossing the border twice in one day (long story), which is obviously odd and suspicious. This strategy worked: at the second crossing, they saw the note left by guards at the previous crossing, and didn't delay me.
So it looks like this time I got careless. Usually I search my carry-on items very carefully for Suspicious Objects, like cutlery or scissors and things---but they've changed some of the rules for this in the US (screwing with our minds, really). So I forgot to remove a fork and knife from my shoulderbag/big-man-purse, and didn't realize it. So imagine my panic when the conveyor belt through the X-ray machine suddenly stops with my bag still in it, and the X-ray operator lady yells "BAG CHECK!" They left me hanging there a little bit while the security officer took her own time to stroll over---and subjecting me to dirty looks from the other passengers who were waiting for their own luggage to go through the silly machine.
Anyway, the bag check officer searched my big-man-purse thoroughly, and then, to my chagrin and consternation, found the fork and knife in the back pocket. "Fork OK, this knife not." It's a flimsy metal table knife with a cheap plastic handle. I stood there and gibbered something about a meal a few days back that I had brought into work and about my normal thorough habits and how stupid I was. She smiled at me in my panic and said, "That's OK, have a safe trip." Then she walked over to a weird cabinet-thing and dumped the knife into a slot and ticked something off on a form. I hope that form doesn't contain my identification---it would suck if I now have a note on my record. We'll see when I go back to the US if I get any trouble, especially after so many untroubled crossings.