In the former case, the caps were hand carried, were explained face-to-face, and the security people were not impressed. Of course, these things were the size of small beer cans, gleaming copper and look like they mean business of some sort. Still . . .

In the latter case, the offending item was packed in checked luggage. That was a mistake. Hand carry it, offer to explain it up front. Have literature showing it and explaining what the heck it does. Be proactive; there's nothing but fear, suspicion and a lack of specific knowledge driving the folks in security. Don't leave it to them to sort things out on their own. I'm not picking on the security folks; I'm saying help them in order to help yourself and protect your gear.

I hand carried a wicked looking tone arm and mc cartridge in their own separate box in their own separate bag on the way back from CES, and sure enough, they wanted to see what this vaguely ray gun shaped thingie was about. I held my breath praying they wouldn't tug on the .3mm silver tonearm leads, and hoping there would be a glimmer of recognition when I said "it's a tone arm. for playing vinyl records." Everything survived just fine, but I was really glad to get it onto the plane.