(Alla Dreyvitser)

On the same July day that Donald Rumsfeld was patted down by airport security at Chicago’s O’Hare airport, I underwent an upper-body pat-down at Reagan National.

I was posing spread-eagle in the full body scanner, in compliance with various mandates of the federal Transportation Security Administration, when something set off a female TSA agent, who began mumbling anxiously into her walkie-talkie.

I leaned forward, trying to hear her description of my offense. I was wearing no shoes and no heavy jewelry, and I’d thrown my belt into a bin along with my BlackBerry, my bulging key ring and an Amazon Kindle.

But something was clearly wrong. Finally, I heard her whisper, “Shiny shirt! Shiny shirt!”

I was, indeed, wearing a very shiny shirt. It was a silver Banana Republic sweater accented with shiny speckles. The agent signaled for me to exit the scanner and pulled me over for further inspection.

The high-tech scanner, bought by TSA at a cost of roughly $150,000, can detect hidden explosives, guns or knives tucked into underwear or ammunition packed into body orifices.

But it cannot, the agent told me, see clearly through a shiny shirt.

My upper-body pat-down was not overly intrusive, and I escaped without suffering the public humiliation of the cancer-stricken 95-year-old who made headlines when she was forced to remove her adult diaper at Northwest Florida Regional Airport.

But as a taxpayer and an occasional long-distance traveler, I departed Reagan wondering how many billions of dollars have gone into producing a sophisticated high-tech airport security system that can be flummoxed by a passenger wearing a shiny shirt. How do we know that al-Qaeda operatives haven’t discovered this chink in the TSA’s armor?

Worse yet, why does the TSA never have to divulge proof that all their random searches, roaming gloved hands and intrusive questions are really protecting America? Where’s the evidence?

Ten years after the 9/11 hijackers passed through major airports without raising questions, have we reached the point where we, as a society, can freely debate whether this system is working and whether all the annoying TSA regulations are actually worth keeping?

Let’s talk hair products.

TSA regulations stipulate that a passenger’s liquids, gels and foams must be limited in size to three ounces. I get that. But many specialty hair products made by major manufacturers simply do not come in three-ounce sizes. Other hair products come in unusual trendy packaging, sometimes with shiny labels, that seems to befuddle TSA agents.

And so, with alarming regularity, hair products are seized. They are thrown into discard bins along with half-filled water bottles and suspicious breast milk. The more expensive the product, I have observed, the higher the chances of seizure.

I first noticed this phenomenon in Kansas City – an unusually strict TSA center, from my observation — when a full container of BedHead Manipulator Sculpting Putty was removed from my bag and seized as contraband. This product had cost me just under $20 at the Ulta Salon in Silver Spring, and I had barely used it. I’ll admit that it had a suspicious appearance — a cobalt blue color and a thick, goopy texture — but no one was going to mistake it for a container of ammonium nitrate.

I found that I had an easier time with the Garnier Fructis line, usually bought for less than $3 an item at the local CVS. I once made it through security in Greenville, S.C., with a mostly used five-ounce jar of styling paste. The forgiving agent warned me that while the jar violated regulations, he would make an exception since the container was nearly empty. This confounded me: Did they really think that a full five-ounce jar of styling putty posed a more ominous risk, as if the putty itself were explosive?

I’ve had so many hair products seized without apology or explanation that I’ve begun to suspect a broader conspiracy. I imagine a rogue cabal of TSA agents with a rented warehouse somewhere near Miami to which they ship all manner of seized high-end hair products for recycling on the black market. Where else could all this stuff be going? I simply refuse to believe that a budget-conscious TSA agent would leave a full container of Bedhead Manipulator in the garbage bin.

But of course, we say nothing, we do nothing. We watch them open our bags and take what they want. We disrobe on command. We stand in the full body scanner and wonder whether someone behind the wall is chuckling at our imperfections.

And we make adjustments — anything to speed us through the process. We wear loafers and elasticized pants. We repackage our precious products, packing pricey styling gel into inconspicuous Hefty sandwich bags.

And from this day forward, when traveling by air, we leave our shiny shirts at home.