12.1The arbiter shall see that the Laws of Chess are observed. 12.2The arbiter shall: 12.2.1ensure fair play, 12.2.2act in the best interest of the competition, 12.2.3ensure that a good playing environment is maintained, 12.2.4ensure that the players are not disturbed, 12.2.5supervise the progress of the competition, 12.2.6take special measures in the interests of disabled players and those who need medical attention, 12.2.7follow the Anti-Cheating Rules or Guidelines 12.3The arbiter shall observe the games, especially when the players are short of time, enforce decisions he has made, and impose penalties on players where appropriate. 12.4The arbiter may appoint assistants to observe games, for example when several players are short of time. 12.5The arbiter may award either or both players additional time in the event of external disturbance of the game. 12.6The arbiter must not intervene in a game except in cases described by the Laws of Chess. He shall not indicate the number of moves completed, except in applying Article 8.5 when at least one flag has fallen. The arbiter shall refrain from informing a player that his opponent has completed a move or that the player has not pressed his clock. 12.7If someone observes an irregularity, he may inform only the arbiter. Players in other games must not to speak about or otherwise interfere in a game. Spectators are not allowed to interfere in a game. The arbiter may expel offenders from the playing venue. 12.8Unless authorised by the arbiter, it is forbidden for anybody to use a mobile phone or any kind of communication device in the playing venue or any contiguous area designated by the arbiter. 12.9Options available to the arbiter concerning penalties: 12.9.1warning, 12.9.2increasing the remaining time of the opponent, 12.9.3reducing the remaining time of the offending player, 12.9.4increasing the points scored in the game by the opponent to the maximum available for that game, 12.9.5reducing the points scored in the game by the offending person, 12.9.6declaring the game to be lost by the offending player (the arbiter shall also decide the opponent’s score), 12.9.7a fine announced in advance, 12.9.8exclusion from one or more rounds, 12.9.9expulsion from the competition.