Hi David,
Went back and read the rule and while your correct it says nothing about the use of any water. What it does say is that the disc(superfeet) can't be clamped or attached to the bench. This is where I would question the use of water, the water and the rubber feet when moistened, may create a bond between the rubber and the concrete and when the base is removed if you have to pry the superfeet from the concrete bench does that constitute attachment? I know for a fact that there were some people that utilized brake cleaner on the bottom of the rubber and and once the base was set on the superfeet they were actually glued to the bench, I watched when it was time to change benches and this person had to use a putty knife to pry them from the concrete! Is not the use of water an attempt to create that bond, I don't know but I will try the water at the Nationals and if in fact the rubber sticks to the concrete then I would say it's going to be a problem!