Something I picked up here on the forums was that when they want to take the knife, tell them they can hold it for you till you come back but to please provide you a receipt with an accurate detailed description and including cost/value. That usually turns them off, but, they have the option of complying, returning your knife to you and not admitting you in with it, or outright trying to rip it off you, in which case the tables are turned and they are now th bad guys.
Funny incident, I work in DC and went to a local fed building to visit the Credit Union, had a briefcase with me. Hadn't been there in a while sowas unaware of new security procedure. When I entered saw a security guard and he said he had to inspect my bag, OK, well I had a William Henry gents knife in it, in its leather case. Guy goes "whoa! no knives allowed in the building, I say Ok so hold it till Iget back just gonna make a deposit, "no, we cant hold them" But I gotta get in here to transact this business should I take a chance and put it outside in the planter, Well thats what I do. I come back after and get my knife from where I hid it in the planter. But check this out. I had forgotten I have a large Sebenza in a nylon sheath in my belt, and a BM705 cliped to my pocket.
I could have carried an Uzzi under my jacket and gone in, but a gents knife in a brief case "whoa"! I'd like thoughtful and intelligent security around but what we're getting is a set of strict parameters that are so narrowly focused on that they'll create other holes for the truly malevolent BG's.
I havent even mentioned the complete greyhound incident, the Sec guard that was checking out thoseolder black ladies with easter looking hats going to visit their grandkids; well the guard at one point took out of a ladies bag a tweezer, and looked at it very closely, turned it around and upside down examining it, squinted his eyes and everything, and hesitantly put it back. Forginve my sarcasm here, but elsewhere sec guards are doing that also, but letting a crazed looking blank staring guy with a fuse sticking out of his C-4 sneaker onto a plane. HEEEELLLPP!!!!