Back when I was in the Army, I unfortunately had a clearance. Which means when you go on TDY, you become a classified material pack mule. In this particular case, in addition to a bunch of sealed envelopes, I had to carry a stickered laptop. Unshockingly, electronics certified to handle classified material are labeled clearly to include the words "US Government Property" and "Protect from unauthorized disclosure". I was also traveling on a government purchased ticket using government ID. But in civvies, because post-9/11.
Sadly didn't have my crypto carrier card as I wasn't carrying crypto material, that one gets you waved past any security checkpoint. TSA had semi-recently been spun up. Naturally US military people are high risk on aircraft, so we got selected for 'random searching'.
TSA: Sign into the laptop and turn it over.
Me: Uhm. No? It's a classified laptop, and I have no proof you have proper clearance.
TSA: We handle government laptops all the time.
Me: Not my problem. You can swab it for explosives all you want, but if it leaves my line of sight, I'm grabbing the real cops to arrest you while I call the FBI to report theft of classified material.
They squawked like a bunch of chickens. Dumped out all of our stuff, triple checked everything. Sadly none of our stuff was easily breakable, because well, soldiers. Not for a lack of trying. They also tried to make us miss the flight. Like we cared, as again, government travel voucher. This was before body cavity searches and sexually assaulting folks, but it got pretty hands on. Laptop however remained within my line of sight and turned off the entire time. You could almost taste the bureaucrat rage. Got the "special" random selection treatment every time I flew (again, usually on govt dime) for a long while afterwards, so I guess they did get the last laugh.
Hell, that's TSA and pretty expected. Fed buddy was made to bin his bottled water, but his loaded Sig and spare loaded magazines were fine. CBP made me dig out receipts to prove the booze I picked up in Ireland were from the duty free shop. I had him hold my SAW (a not small belt fed machine gun) while I dug around for the bottles and receipt. He didn't even blink. Never underestimate a government employee's ability to follow stupid rules.