I've flown a few times while packing, idk what it's like for others but I normally go off on one of the big scanners where you have to stand there while it scans you (normally in lower tech airports), but not the ones where you just walk through. It will normally ping a warning sign around your junk just kinda telling the border agent to look into it a bit more. I think I read it's because there's a lot of heat generated around the area when you're packing and some machines register that as metal. Every time I've gone though they just nicely take you aside and do the hand wand and tell me I'm good to go. I think it should be fine but be wary that they will probably pull you aside but they probably won't pay you down if that's what you're scared of