What constitutes a "tournament error" concerning deck registration?

A tournament error regarding deck registration is primarily defined as failing to register all cards accurately. Accurate registration means that every card in the deck, including the sideboard, must be listed properly to ensure compliance with the tournament's format rules and to maintain a fair playing environment.

When players do not register all the cards correctly, it can lead to discrepancies during gameplay. For example, if a player has a card in their deck that they did not register, it can be considered an unfair advantage, as opponents are unaware of its presence. In competitive play, the integrity of the game relies heavily on accurate information being shared among participants and judges.

Other options may reflect important aspects of deck registration, but they do not constitute a tournament error to the same degree. The type of sleeves might not affect the game state directly, forgetting a player’s name could be a clerical oversight, and not including a sideboard might be a rule violation, but it often does not directly impact the integrity of the deck itself as failing to register all cards does. Therefore, the emphasis on accurate card registration solidifies its classification as a tournament error.