Back in the days when I worked tech (mostly theater) we had a tradition. On load-out (clearing the space of all gear, set pieces, equipment, etc.) the crew would report to the chief when they were done. At some point the crew chief would call "Idiot check!" and people would go look around for lost items, forgotten rolls of tape, dropped wrenches, etc. As in "Don't leave that behind, idiot."
At some point this morphed into a call and response where the crew chief would call, "Idiot check!" and everyone on crew would respond "Yo!" with raised hands as though the chief was taking attendance. I've taught this tradition to my family - the boys think it's hilarious - and we do it when we're checking out of hotel rooms.
This morning I needed to be downstairs earlier than usual, checked out of the hotel, for the group walk over to the conference center, sans breakfast. I made it and when I got to the conference center I realize I've left my laptop in the hotel room.
Fortunately I was able to walk back and get the computer - it was still in the room where I'd left it - but you can bet I did another idiot check before I left the room.