Pretty much any security check worldwide, not just at airports, which involves this level or greater, has the subject turn their palms up to assure that there is nothing in their hand, including stuck to it. If you can't physically do that or you can do it but it hurts, just say so. Officers will either ignore it or look under the hand. Just takes a bit longer.which may or may not delay you and the person behind you waiting for the Officer.

How many of those security checks worldwide are done in a Whole Body Imager which has the sole purpose of finding anomalies?

Shouldn't matter how the hands are held as long as they are not pressed up against the body.

Please, stop calling them officers; they are screeners.

I've never been told "palms up." When I've been frisked, I've only been told to put my arms out straight.

I'm told palms up every time I get a manual screening. I had assumed this was just to verify I'm not concealing anything in my hands. Of all the indignities of the screening procedure, this one rates as "least concern" for me personally.

Wear a long sleeve shirt and stand with your hands extended at your sides.

Look at the looseness of the shirt sleeves and body.

Turn your arm 90 degrees at the elbow and place the hands palms up. Your shirt and the sleeves get tighter on your arms and sometimes the body, making it easier to see a concealment.

Not defending them overall though, as I preferred the "so they can see if you have something in your hands" answer.....................

Isn't the whole purpose of the Whole Body Imager to detect items concealed on a person?

No. Please do call them "investigative officers", so that 28 USC 2680(h) applies and there's FTCA liability.

Nice to see you back!

What good does that do if TSA doesn't call them "investigative officers" - they'll just say there is no such position in the organization.

I've been busy. :-P

Just reinforcing the reminder. Obviously what you say has no legal effect per se, but if people continue to litigate the issue with FTCA claims, that helps. Currently there's a circuit split on the matter. The Pellegrino case whose amicus I linked to is currently pending; a win in that would be pretty important.