BD1791
Are you working at places that are rather religiously conservative (or more bible oriented, if you like it), or rather socially liberal? I'm asking because I'd assume you could get a maybe unexpected sort of understanding in the former sort of places.
Be that as it may, since you probably can't design the places, anyway, how about starting to take the PR into your own hands and at an occasion of your choosing - instead of anxiously waiting until you are forced to answer questions in a moment beyond your control.
For instance, choose a guard you know and feel comfortable enough with. Look for a time when it's rather relaxed at the checkpoint and a suitable place for talking (maybe there is some office nearby or at least a discrete corner where you can talk without more people listening).
Personally I'd not wear your equipment for that talk yet. IMO it could backfire when you have to admit that you have been "smuggling" in that stuff beyond the checkpoint, already. They are the authority concerning the buildings security; and saying that you effectively fooled them by hiding metal items for days wouldn't seem a great place to start, But that's up to you to decide...
Then I'd open that for several reasons you plan to wear protective metal underwear in the near future.
You just wanted them to know in advance, because you expect to show-up at the scanner and you wanted to simplify and speed up the procedure. You might also mention that you anticipate it might provoke questions and it was easier to you to answer them now instead of when everyone is waiting in the line. (Which is probably true.)
See how they react. Maybe they has questions, maybe not. It might be a completely dull affair. Or - if there is genuine interest and you deem them worthy - you might get into a bit more details. In this case you might add that many people name the stuff you are going to wear chastity devices, but that they fulfill more than one purposes for you (e.g. you could mention the use case of anti-sexual assault protection - which is both true and rather simple to understand).
In any case, keep in mind: You made a perfectly legal, well-though choice in an important life topic. You are fine. Your partner is on board. It's not a bigger than life issue, and on the same page, you neither have to be ashamed - nor have to hide it more than usual rules of decency demand for any other underwear. You considered it rather private, you just had to explain because the scanner would bring it up eventually, anyway.
And if anyone actually comes up with the "chastity can only be medieval or fetish" pigeonhole thinking - which unfortunately is still portrayed in too many media - you could say that it's different for you. Besides that these media representations are ill-informed and sometimes just click-bait. You don't have to argue, unless you consider it important to set things right.
Of course it's all up to you how much you open up. Yet I think in your respectable position you have a very strong base to actively shape what will be said in the future. At least that is what I'd do. And let's face it, sooner or later you will have to answer these questions. Why not getting control of the playfield in advance?
You can go on with this as long as you like. Don't wear there yet, just talk. One after the other. Get experience with these talks. Talk to more of the security personnel. Different shifts, different places. If you get along with someone pretty well, you can announce that you wanted to tell some of their colleagues as well, before you actually wear, so that replacements or different shifts know, too. Or maybe your favorite guard even does this for you.
Don't force yourself into a fixed time and place where the likelihood that you wear your devices and are confronted with completely uninformed guards is too high. You can choose the time for this. Your plan, your underwear, your life. Only start entering the courthouse with your metal stuff when you are pretty sure at least someone at the checkpoint is on board. If you are called out at the security checkpoint, address that person and refer to your prior talk. That way there is less basis for rumor, and much more informed understanding instead.
And, who knows, maybe there is one or the other, who eventually (secretly or openly) finds you the coolest and most decent attorney they've met so far ...
