Golf is unlike any other sport because the player is both the athlete and the referee. The game is built on integrity and the ability of someone to call a penalty of themselves or others. Unlike other sports, most golf rules can be interpreted differently, which is a completely different conversation.
On the Course
All types of things happen during a round of golf and it can be hard to keep track of everyone's shot during the round. A player may say that their ball is in a divot so they kick it to the side or that their ball is in a depression so they get relief. These are a couple of examples where the Rules of Golf are interpreted differently. Courses usually post local rules that are specific to their course or area and in tournaments there are definitely rules that are specific to that event. No matter what happens there will be someone who tries to take advantage of the rules.
If you are in a tournament and someone is taking an unfair drop, you need to call them out and make sure the other players in the group are aware of the situation. There are two types of cheaters: ones who blatantly cheat and ones who take advantage of the rules to give themselves a jump on the field. For the latter, the best thing to do is to have that player play a second ball and following the round you can ask the golf professional for the ruling.
Here are some things to watch out for:
Coin Mover
There are so many unwritten rules to follow on the putting green that it's tough to watch each player's every move. The coin mover is the guy who will move his coin either as he's marking his ball for the first time or when he's getting ready to putt and he drops his ball closer to the hole. Not all greens are perfect, so it's important not to let anybody get an unfair advantage.
Free Drop Guy
Taking a drop is one of the most common Rules of Golf practices that you see everyday. You take drops for water hazards, hitting it out of bounds and for manmade obstructions to name a few. The wording, "nearest point", is what's used when describing where to take a drop. This can easily be misinterpreted and it often is by the guy who will drop where ever he feels is the nearest point of relief. Make sure when someone is taking a drop that they don't move closer to the hole and that the nearest point of relief is where the ball ended up, not where it is clear of obstructions.
Score Changer
This player will change their score a couple holes later, so when you go to tally up the scores at the end of the round, they have something different. The only way to counter this is to keep track of every single shot your playing partners take, which is not likely. These players usually do this over and over, so if you don't agree with their score you can just not sign their card and the score won't count.
Bad Sportsmanship Guy
This falls more into the unwritten rules of golf, but it still has its place in a cheater's list. Players who don't care for their playing partners during a round can be a serious nuisance. They may stand in an awkward place during your tee shot, cast a shadow over your putt or ruffle through their bag as you hit. The best way to deal with this person is to take your time and politely ask them to move or wait until after you hit. Don't rush your shots because someone is making you uncomfortable.
Water is Everywhere Guy
Temporary Water is another portion of a rule that is easily misinterpreted. Temporary water is defined as any temporary accumulation of water on the surface of the ground (such as puddles from rain or irrigation or an overflow from a body of water) that can be seen before or after the player takes a stance (without pressing down excessively with their feet) and is not in a penalty area. This player claims that there is temporary water because they jump up and down on the grass and water comes gushing out, that is not temporary water. They must play the ball as it lies and cannot take a free drop.
Hopefully these reminders can help you during your next round of golf!