I got presented something akin to the plaque below by some US colleagues at the end of a particular tour, except it was a AK47 bayonet and scabbard.
I carried in my daysack when I flew out as I had no room in my bergen. I flew into Lyneham and stayed there in transit for a night as I was booked on the next Herc flight to Hannover. On being called forward that morning, I forgot all about it and shoved the daysack through the X-Ray scanner. The snow drop nearly fell off her seat and shouted as if I was an imminent danger. I was suddenly surround by Snowdrops menacingly as they pulled out the contents of the bag and decided if I needed executing or not. The disapproving looks and tuts meant I wasn't going to get away from this lightly.
Then the RLC Liaison movements SNCO strolled over, checked that the bayonet was secured properly to the plinth and with rolled eye's, handed it back to me, told me not to be a prick again. I proceeded through to the aircraft doing the walk of shame between the RAF.
I got called to security screening at my local international airport ahead of a holiday in London. They'd seen an image of something in my kit bag they could not identify by X-ray and wanted to see it in person. While I was undoing the bag, I asked the older of the two screeners if perhaps he'd been in the Navy. He said he had been. Then you will recognize this USN Mk II "talker's" helmet design to be worn over headphones.
"Why are you taking that to London?"
"I'm giving it to the Imperial War Museum because the one they have looks like **** and this one had never been issued."