Agreed, but the TSA goes into similar spasms over harmless pieces of brass.
Went to a relatives funeral who had a gun-salute from the local VFA... put a spent 30-06 casing from the volley in my bag and went straight to the airport after the service.
I only had a single small carry-on and didn't even think of the casing in there... of course it pops up on the x-ray and I get called back for a bag-search... TSA was very cool when I told him why I had the spent casing. I think a lot of your interaction with the TSA depends on your attitude. Perhaps my experience was partially due to my clean-cut military appearance and showing my military ID card instead of drivers license when they asked to see an ID back in the inspection area, but I'm confident that my friendly demeanor, big smile, and understanding attitude went a long way. I was back there for about 2 minutes and then on my way to the gate, shell casing in my pocket.