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19-1. By Outside Agency
If a ball in motion is accidentally deflected or stopped by any outside agency, it is a rub of the green, there is no penalty and the ball must be played as it lies except:

a. If a ball in motion after a stroke other than on the putting green comes to rest in or on any moving or animate outside agency, the player must, through the green or in a hazard, drop the ball, or on the putting green place the ball, as near as possible to the spot where the outside agency was when the ball came to rest in or on it, and

b. If a player's ball in motion after a stroke on the putting green is deflected or stopped by, or comes to rest in or on, any moving or animate outside agency, except a worm, insect or the like, the stroke is canceled. The ball must be replaced and replayed.

Exception: Ball striking person attending or holding up flagstick or anything carried by him — see Rule 17-3b.

Note: If the referee or the Committee determines that a player’s ball has been purposely deflected or stopped by an outside agency, Rule 1-4 applies to the player. If the outside agency is a fellow-competitor or his caddie, Rule 1-2 applies to the fellow-competitor.

(Player’s ball deflected or stopped by another ball — see Rule 19-5.)

19-2. By Player, Partner, Caddie or Equipment
If a player's ball is accidentally deflected or stopped by himself, his partner or either of their caddies or equipment, the player incurs a penalty of one stroke. The ball must be played as it lies, except when it comes to rest in or on the player's, his partner's or either of their caddies' clothes or equipment, in which case the ball must through the green or in a hazard be dropped, or on the putting green be placed, as near as possible to the spot directly under the place where the ball came to rest in or on the article, but not nearer the hole.

Exception 1: Ball striking person attending or holding up a flagstick or anything carried by him — see Rule 17-3b.

Exception 2: Dropped ball — see Rule 20-2a.

(Ball purposely deflected or stopped by player, partner or caddie — see Rule 1-2.)

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