When you sign a scorecard, the only numbers that need to be correct are your course handicap (if applicable) and your scores on individual holes. If you total your round's score incorrectly, there's no penalty. It's the committee's responsibility to tally them (and apply the handicap). RULE 33-5
• If you sign for a higher score than you actually had on a specific hole, there is no penalty, but you have to keep that score. If you sign for a lower score than you really made on a hole, you'll be disqualified. RULE 6-6D
• A marker is someone who keeps your score during a competitive round. At the end of the round, you have to make sure the scores the marker wrote down are correct. If you find an error, you and the marker can correct it before you turn in the signed card. Notify the committee if the marker isn't present—if you turn in the card before resolving the issue, you'll be disqualified. DECISION 6-6B/7
• In match play, if you give incorrect information—even if it's by accident—to your opponent about the number of strokes you've taken while playing, or after completing, a hole, and your opponent hits a shot or lifts her ball before you correct yourself, you lose the hole. RULE 9-2
• In stroke play, there is no penalty for giving incorrect information to a fellow-competitor, unless it was done to mislead. Doing so would be a serious breach of etiquette, resulting in disqualification. DECISION 9-3/1, RULE 33-7
There are limits to the maximum per-hole scores you may post to update your Handicap Index (known as Equitable Stroke Control). But that doesn't mean you can necessarily pick up your ball when you reach your max on a hole. In stroke-play events, keeping your actual score on a hole is still required. Here is the ESC table (right):
PLAYER: Carl Pettersson
EVENT: U.S. Open
RULES IN QUESTION: Decision 14/1.5; Rules 18-5, 20-7
SITUATION: During the second round, Pettersson was in the fifth fairway, mid-backswing, when an errant drive hit his ball. He stopped his swing and stepped away. Pettersson then replaced his ball and finished the hole.
VERDICT: No penalty. If Pettersson had played from the ball's new position, he would have received a two-stroke penalty for playing from the wrong place. There's also no penalty for stopping his swing at the last second to avoid making a stroke (even if his club had passed over the top of the ball's position). The key is whether the player intended to strike the ball, and in this case he didn't.