That means that the bunkers are treated as ground under repair through the green from which play is prohibited. This is the only way that they can be taken out of play under the rules. See Rule 25 for procedure: To locate the nearest point of relief you find the nearest point outside of the ground under repair from where the ball lies in the bunker, and where you can take your stance with the club you would normally use for that shot. That point must not be closer to the hole than where the ball lay in the ground under repair, and you must take complete relief for both stance and lie. Once that point is determined, then you can drop in an arc of one clublength, not nearer the hole than the NPR. The ball must not roll closer to the hole than the NPR, nor more than 2 clublengths from where it first hits the ground, and it must not roll back into interference from the GUR. Dropping the ball back on any line away from the hole is an incorrect procedure. That would only apply if it was a water hazard or if the ball was declared unplayable under Rule 28.