He is lucky he was not in Atlanta. Similar thing happened to a young bride headed off on her honeymoon. She had borrowed Mom's suitcase which had a .22 handgun in it. The bride discovered it, informed the police and spent her wedding night in the Atlanta jail.
They normally arrest in cases such as this. (No good deed goes unpunished).
TSA--what a bunch of screw ups. But what can one expect from a government monopoly?
I think the general attitude by authorities about gun ownership in Montana vs Atlanta might have a lot to do with the different outcomes.