Joe,
My point was that the major problems at bethpage began in the fairways with drainage rather than the greens. By the time the greens are oversaturated at Bethpage the fairways have already become unplayable, therefor tarps on the greens at Bethpage serve no real purpose as an aid to allowing for more and better play.
Also, as you so rightly put it, the water on the TARPS would also have to go somewhere and I would think that with all of that water not soaking into the greens that the surrounds, especially the bunkers, would be FAR worse and make the course then unfair and unplayable that way as well.
There isn't a single person who wants to see Bethpage Black play firm and fast more than me... but rain is part of the game and it is played out of doors.