Unrelated to the Mall, but related because someone mentioned gun powder residue.
Back in the old days of freedom and unrestricted travel, precovid, I traveled a lot.
I was on an early flight one Monday morning, going out of Logan to Germany.
I had spent the previous night reloading, I had been on the Dillion 650 and hand loaded some 308.
I was randomly flagged for the finger swab, I asked what it looked for.
"Highly sensitive device, it can detect if you been near explosive or gun power in the last 48 hours"
Needless to say, but I was heading to the gate a few moments later.
So as long a bad guy doesn't shower or wash their hands, we safe.