> btw don't try that with something that is on their list like ammo, even one bullet. Your life will be ruined.

I've done that too. You travel so aggressively, eventually you have some oopsies.

I went through a stint where I was driving for work, and working with a bunch of people in a woodsy state. A guy would take us shooting, and he asked me to buy a box of ammo to replace what I shot - so 20 bucks for 500 rounds of .22 caliber ammo.

Next time I flew was the first time I had actually been selected for TSA precheck - you know, the Trusted Traveler program and you can guess what I left in my carry-on. I was very apologetic and had to talk to a very grumpy city police officer, but it was fine. I paid a fine of $130, and that was it - they offered to let me check my bag to keep the munitions too!

It has never even come up with my 3 Global Entry interviews either. And yes - I live in a blue state.

Obviously don't do it. It wasn't a problem for me, but very much YMMV. I know someone else who got dinged for having a banana they bought in a foreign airport, and that continues to come up in their Global Entry interviews. Live ammunition < Bananas, apparently.