Thanks for bringing this point up. Damaging the rim of the putting hole is definitely not cool! It can ruin a golf hole and thus an entire round for everyone who comes behind you that day.
I would like to add to your comments. First, what do the Rules of Golf say? If a player damaged a hole by carelessly using his putter to dig the ball out, what is the consequence? And what do the Rules say about repairing the damage?
The Definitions under the Rules of Golf define a "Hole" as follows:
Hole
The “hole’’ shall be 4¼ inches (108mm) in diameter and at least 4 inches (100mm) deep. If a lining is used, it shall be sunk at least 1 inch (25mm) below the putting green surface unless the nature of the soil makes it impracticable to do so; its outer diameter shall not exceed 4¼ inches (108mm).
The Committee has the responsibility to see that all competitors play the same course each round. This finds expression in Rule 33:
33-2. The Course
a. Defining Bounds and Margins
The Committee shall define accurately:
the course and out of bounds,
the margins of water hazards and lateral water hazards,
ground under repair, and
obstructions and integral parts of the course.
b. New Holes
New holes should be made on the day on which a stroke competition begins and at such other times as the Committee considers necessary, provided all competitors in a single round play with each hole cut in the same position.
Exception: When it is impossible for a damaged hole to be repaired so that it conforms with the Definition, the Committee may make a new hole in a nearby similar position.
The Players and their caddies have the responsibility to avoid affecting play by influencing the position or movement of the ball:
1-2. Exerting Influence on Ball
No player or caddie shall take any action to influence the position or the movement of a ball except in accordance with the Rules.
(Removal of movable obstruction — see Rule 24-1.)
PENALTY FOR BREACH OF RULE 1-2:
Match play - Loss of hole; Stroke play - Two strokes.
Note: In the case of a serious breach of Rule 1-2, the Committee may impose a penalty of disqualification.
Decisions under Rule 16 set out the procedure for repairing a damaged hole:
16-1a/5 Touching Inside Edge of Hole
Q. Prior to putting, a player touched the inside of the hole. Should he be considered to have touched his line of putt in breach of Rule 16-1a?
A. Yes, unless the hole was materially damaged and the player was entitled to repair it. In this connection, see Decision 16-1a/6.
Player Repairs Hole After Holing Out But Before Opponent, Fellow-Competitor or Partner Holes Out — See 1-2/3.5.
16-1a/6 Damaged Hole; Procedure for Player
Q. Prior to putting, a player discovers that the hole has been damaged. What is the proper procedure?
A. If the damage is not clearly identifiable as a ball mark, then:
If the damage is such that the proper dimensions of the hole have not been changed materially, the player should continue play without repairing the hole. If he touches the hole in such circumstances, a breach of Rule 16-1a occurs.
If the proper dimensions of the hole have been changed materially, the player should request the Committee to have the hole repaired. If a Committee Member is not readily available, the player may repair the damage, without penalty.
If a player repairs a materially damaged hole when a Committee Member is readily available, he incurs a penalty for a breach of Rule 16-1a.
The Decisions under the Rules address the following situation:
1-2/3.5 Player Repairs Hole After Holing Out But Before Opponent, Fellow-Competitor or Partner Holes Out
Q. After holing out, a player observes that the edge of the hole is ragged. He pats the ragged edge with his hand and smooths it. Does the player incur a penalty under Rule 1-2 if his opponent, fellow-competitor or partner has not holed out?
A. If the player smoothed the edge of the hole as a courtesy to following players, which seems likely, there is no penalty under Rule 1-2. However, he incurs a penalty under Rule 1-2 if he smoothed the edge of the hole for the express purpose of influencing the movement of the opponent’s, fellow-competitor’s or partner’s ball.
Since the player had holed out, he is not subject to penalty under Rule 16-1a.
If a four-ball competition was involved and the player’s partner had not completed the hole, the partner is subject to penalty under Rule 16-1a — See Definition of "Partner."
The Decisions also address when a cup liner is not deep enough (at least 1 inch deep):
16/4 Hole-Liner Not Sunk Deep Enough
Q. Players discover that a hole-liner is not sunk at least one inch below the putting green surface as prescribed in the Definition of "Hole." What should they do?
A. The players should call the matter to the attention of a Committee member if one is present. If feasible, the Committee member should attempt to have the fault corrected.
However, the players must not discontinue play in the meantime, because correction might not be possible and, if possible, might take considerable time.
16/5 Ball Strikes Edge of Hole-Liner and Bounces Out of Hole
Q. A player’s ball struck the rim of a hole-liner, which had not been sunk deep enough, and bounced out of the hole. Should the ball be considered holed in such circumstances?
A. No. Under the Definition of "Holed," the ball must be at rest within the circumference of the hole.
These Rules and Decisions don't directly and expressly address the situation of the golfer digging his ball out of the hole with his putter. But the rules definitely imply that any voluntary conduct that damages the hole before others have finished playing the hole constitues affecting the movement of the ball, and so is a violation of Rule 1-2 (Loss of Hole or 2 Stroke Penalty, and DQ in extreme cases).
The repair of the damage is supposed to be by the Committee, but if a player repairs the damage after holing out, and does so merely as a courtesy, that's fine. However, a player who has not yet holed out cannot make the repair, regardless of his doing so merely as a courtesy, since he violates Rule 16-1a's ban against touching the green when his ball is on the green still in play.
A second area of added comment is -- if the golfer is still going to dig the ball out, especially while practicing many putts on the practice green -- how can this be done while avoiding damage to the hole?
Let's admit it -- even pros dig the ball out. So what's the way to do it/ To me, the shape of the putterhead has to allow digging to start with, like a flange putter. Mallets don't usually work, nor do odd-shaped putters. The toe has to trap the ball against the liner at the bottom of the cup, and then the toe is slid up the liner to toss the ball out. When doing this, care must be taken to a) avoid leveraging the hosel of shaft against the lip, and b) letting the toe touch the dirt above the top edge of the liner. It's sort of like getting an egg out of a pot with a spoon.
Cheers!
Geoff Mangum
Putting Theorist and Instructor
PuttingZone http://puttingzone.com
Golf's most advanced and comprehensive putting instruction.