Rosey, I have shot plenty of Trap and have seen on many occasions the line called cold, the shooter that was up had to unload and show clear. Where this guy was shooting either they don't know how to run a line, or he was not at an event.
Nice thing about an O/U, simple to show clear!
I would always rest the gun on my sneaker until it was my turn to load and call for the target. But my gun wasn't fully closed, O/U, and there certainly was NOTHING in it!