Interesting match play ruling
Whether Picking Up Opponent’s Ball Is Concession of Next Stroke.
Q: In match play, A holes a putt and, thinking she has won the match, picks up B’s ball. B then advices A that she (B) had a putt to win the hole. Did A concede B’s next stroke when she picked up B’s ball?
A: No, A incurred a penalty of one stroke under Rule 18-3b; B must replace her ball and now has two putts to win the hole.
Rule 18 Ball at rest moved
Rule 18-3 BY OPPONENT, CADDIE OR EQUIPMENT IN MATCH PLAY
Rule 18-3b Other than during search
If, other than during search for a player’s ball, an opponent, her caddie or her equipment moves the ball, touches it purposely or causes it to move, except as otherwise provided in the Rules, the opponent incurs a penalty of one stroke. If the ball is moved, it must be replaced.