One tell would be if the photographer was shooting in aperture mode or shutter mode. It is usually what is most important at the time. Like if he wanted a shallow depth of field - aperture mode. If the sky was the background all the time this is not necessary but I heard he wanted the flag in the background as well, maybe he opted for it to be blurry. Then the shutter speed would be set automatically.

If he was using shutter speed priority and dialled in 1/8000, the shortest available. I would take him in for questioning, highly suspicious.