If a player has marked cards, what must they do?

When a player is found to have marked cards, the appropriate action is to replace these marked cards with unmarked cards. This is necessary to maintain the integrity of the game and ensure that all cards in play are indistinguishable from one another. Marked cards can provide an unfair advantage, as they may allow a player to know information about their cards that the opponent cannot see.

Replacing marked cards with unmarked ones helps to restore fairness to the game by eliminating any potential advantage derived from the markings. It is essential for the game environment to be equitable, and using cards that do not have any distinguishing features is a fundamental aspect of that fairness.

Continuing to play with marked cards would compromise the game's integrity. Replacing them with other marked cards would not resolve the issue, as it would perpetuate the problem. Furthermore, replacing only one marked card would be insufficient, as any marked card in a player's deck can skewer the balance of play and player interaction over the course of a match. Thus, the action of replacing marked cards with a full set of unmarked cards is the correct procedure in this situation.