What happens if a player calls a judge after realizing they have not de-sideboarded?

In a situation where a player realizes they have not de-sideboarded after they have already drawn their opening hand, the appropriate remedy is that the player can redraw their hand with one less card. This is a way to address the oversight while maintaining the integrity of the game.

When a player sides in cards from their sideboard, the expectation is that they will return to their original deck configuration before the game starts. If they forget to de-sideboard, it effectively means that their deck has a different composition than intended when they drew their opening hand. By allowing them to redraw their hand with one less card, the game compensates for the unintended advantage or disadvantage caused by the additional card in their hand due to the unresolved sideboarding action.

This approach balances fairness for both players by not penalizing them too harshly for what could be an honest mistake while still allowing for the proper resolution of the game state. The other options suggest severe penalties or actions that do not align with how such infractions are typically handled in Magic: The Gathering tournaments.