Motte and Bailey?

This morning, we took the dogs to Banff Beach for a walk. It was lovely and still. You can see Hugo is putting the finishing touches to his Castle.
I wonder where he got all the stones from!
The real mystery however, is in the extra.
The man stood there for about half an hour with his flag.
I have no idea what he was doing.
I really love this “Castle” song https://youtu.be/TTqi7iEZEWA?si=MyR-ZeHh10gsFIUt