In curling, there are a few violations that you should be aware of. The majority of these violations deal with making contact with the stones, either by a person or another stone. There are also violations related to running out of thinking time, if you are playing a game of that format. The main five violations that can occur in a game of curling are:
The free guard zone, also known as the five rock rule, exists for the first five rocks of an end. If an opponent tries to remove a guard from play before the first five rocks of the end are thrown, the guard in-play returns to its prior location, and the opponent's stone is removed from play.
The thrower must release a stone before it reaches the hog line. A hog line violation occurs when the thrower fails to release the stone before the front edge of the stone reaches the hog line. If a hog line violation occurs, the stone is immediately removed from play. Have you ever seen a green light flash on the stone as it travels down the ice? The green light indicates that a hog line violation was not committed. If a player committed a hog line violation, the light would flash red.
As curlers sweep the stone, there is a rare occasion in which a broom, curler, or other object will make contact with the stone in motion. For example, let's say a hat falls off someone's head on to the stone. This is called burning the stone because a foreign object made contact with the stone as it travelled down the ice.
If a curler burns a stone before passing the hog line, it is immediately removed from play. If a curler burns after passing the hog line, the opposing skip decides what happens to the stone. As we have learned, curling is a game of camaraderie and respect, so the skip may elect to leave the stone where it is. Usually, the stone is travelling slow enough that the foreign object will not significantly alter the trajectory of the stone.
When a team runs out of thinking time, they are not allowed to throw any more stones in the game. Thus, it is guaranteed that the team will lose the game. Out of all the violations, this one is the most significant, as a team loses the entire game rather than having a stone removed from play.
It is expected that all stones remain where they are during an end, and can only be moved by making contact with other curling stones. There is a chance, however, that someone accidentally removes a curling stone from play. Should this happen, the opposing skip will decide where the stone should be placed. Usually, this means that the stone is placed back at its prior location, and the game continues.