During the winter at my course white ropes and poles are immovable obstructions and relief may be taken under Rule 16.1b. That makes sense but yesterday in a friendly match my opponent's ball deflected off a rope. He stated he could play the shot again arguing it was the same as overhead cables. I was unsure as I thought that was specific to overhead cables only. Also if this was indeed the case, could he have the choice - ie. replay if he didnt lke the outcome but ignire if he did?