Sorry gentlemen, I know flying under bridges is against the law (in any country) but with such a large bridge and such a docile aircraft it is a piece of cake for any private pilot with more than 500 flying hours. But this is stupid and dangerous and just because it is a spectacular air race, anything is allowed ?
A friend of mine was in a Hughes 500 helicopter that went into the water when the pilot tried to fly under a bridge in Kentucky in the dark, and the skids caught the water and flipped it. He and the pilot survived, but he thought he was going to drown before he got out. This was when he was in the Army and was an Army chopper. The taxpayers took a beating that day.
Moral of the story is: Don’t be stupid in the dark: Use daylight, it is free (and usually clear) (I flew commercially for 37 years, survived it all, but tried to do most of my stupid stuff in broad daylight)