I once lived and worked in a small store in rural Australia. When I left the job, I threw my box cutter in my backpack at the end of my shift without thinking.
They flew me back to the nearest city when I left, then from there I flew to Bali and back, then eventually I flew home. Every time I flew. I used that backpack as my carry on luggage. It was found when I landed after that final flight. I’d totally forgotten it was in there, and it had been scanned for all of those flights.