Oddly enough, when I was working my staff was regularly walking around an explosives factory and an explosives filling factory, and I'd visit the factories occasionally too.
We often wondered what would happen to us if we got pulled over and tested at airports and we failed the test, for having trace amounts of RDX/TNT or gun propellant on our shoes. We never got tested, so we never found out.
Regards,
Renato
I got tested once. I was in full military cams though, with DOD ID. Had been on a shoot earlier, was flying up to say good bye to my brother. I openly admitted I had been in the presence of gunpowder earlier in the day. They accepted my DOD Id and I was on my way. Was amusing they randomly selected me. Funny enough, I came back 2 hrs later from a larger airport, they did not swab me ha.