Some of the top golfers in the world have been unable to distinguish between sand bunkers and waste areas, also known as waste bunkers. In 2010, Dustin Johnson played a shot out of a sandy area outside the ropes on the 72nd hole of the PGA Championship at Whistling Straits in Kohler, Wisconsin. Assuming he was in a waste bunker, he grounded his club behind the ball in an area that had been defined by the PGA of America as a sand bunker. The two-stroke penalty for grounding his club in a sand bunker knocked him out of a playoff. Usually, however, it's pretty easy to tell the difference between bunkers and waste areas.