Leave moneybelt on through airport security ?

It depends on what kind of security you are going through. If you are going through a metal detector, it may set off the alarm if it has metal zippers. I always take mine off, just to avoid wasting time. I also take off my belt, and since my money belt is the "hidden pocket" kind that hangs from the belt, it comes off with it. I put both in my carry on (along with everything in my pockets), then re-dress after the metal detector. But, if your moneybelt doesn't set off the metal detector, you should be able to keep it on. However, if you are going through one of the newer scanners (the kind where you stand sideways with your hands over your head, which takes a "naked picture" of you), then you MUST remove the money belt, and your pockets MUST have nothing in them. It's not optional with these kinds of scanners. This applies to the US; other airports may have different rules or procedures.

Jack, I normally place my Money Belt in my carry-on when going through security, as that usually avoids any problems. As the others have mentioned, the specifics will depend on the security screening measures in place at the airport (I don't recall going through full body scanners at SEA when I was there in January). The zipper could trigger the metal detector, which means you'll be the recipient of a "groping" and will then have to take the Money Belt off so they can run it through the scanner. It's all rather embarrassing when that happens, as you're holding up the queue and of course have to display to everyone nearby that you have a Money Belt and the location you keep it. If you leave the Money Belt in your carry-on, it's easy enough to put it on either before your flight when you're through security, or during the flight (use the washroom in both cases). Happy travels!

Most international airports these days have switched to the high-tech body scanners. So everything must be removed from your pockets (including paper) and money belts must come off. The scanner will detect them even if the zipper is plastic.

I have a non-metal neck-hanging moneybag. I have never had it questioned.
I have been selected for the intimate survey you describe. The moneybelt has never been a cause for focus - it's been the random code on my ticket or the unusual reason I was traveling internationally (Canada only) The pat-down is more uncomfortable to the TSA (I only know USA)people than to me. I have refused the option of privacy when that happens because they are observed by the crowd. My money bag has no metal. It's Eagle something, ten years old.

Thank you all for the quick responses !! To play it safe, I think I will remove my moneybelt and put it in my carryon to prevent the potential for any pat downs, etc.

You should remove it. I put mine, along with any change or anything else in my pockets, in a Ziploc bag in my carryon. Then I reassemble after security.

I forgot to take mine off the last time I flew. Our airport has the body scanning type machine. I had to go with two male security men into a private room and take it off, after a lot of questioning. Then they had me go with them, and they ran it through the scanner by itself. It all took about 20 minutes. I'll not forget to take it off from now on.

I always try to leave it on, and I always get "told" to take it off by TSA. It's such a pain and who really wants to have their valuable taken away and scanned by the sticky fingered TSA these days? If you're traveling with someone have them go in front of you and get completely through the machine BEFORE you send your valuables through the scanner. Have your partner keep their eye on it as it goes through that scanner.

Leave your money belt in your carry-on while you go through security screening. Even if you get lucky and only have to walk through a metal detector instead of the Whole Body Imaging machines, you might set the detector off anyway or get picked for a 'random' secondary and when you get patted down, it'll be found and you'll have to take it off then and get it inspected. (And sadly, given the many cases of theft that have been reported on in the screening process, you don't want them 'inspecting' your valuables if you can help it. I put all my valuables except my passport inside my carry-on and lock it. There is no requirement that your carry-on be unlocked, only that you unlock it if it is picked for secondary inspection. So, keep your money belt (and your smartphone and jewelry and any other expensive goodies) in your locked carry-on, and put it on after security in the privacy of the restroom.