What can lead to a Disqualification (DQ) in a tournament?

The use of marked cards can lead to a Disqualification (DQ) in a tournament because it is considered cheating. Marked cards indicate a player's intention to gain an unfair advantage by providing themselves with information that should not be accessible during the game. This violates the integrity of the tournament and the expected fairness in gameplay.

In competitive Magic: The Gathering, maintaining a level playing field is essential, and using marked cards is a clear breach of this principle. Cheating, whether intentional or inadvertent, can result in severe consequences, including disqualification, regardless of the player's intent. In this context, other options like minor gameplay mistakes, forfeiting a game, or taking longer than the time limit typically result in warnings or other penalties rather than disqualification, as they do not directly imply an attempt to cheat or manipulate the game.