The Secrets of Sportsmanship

Amir is playing against Nemo at a large Competitive REL Modern event. On his first turn of the match, Amir plays an Island and puts an unchecked Shadows over Innistrad checklist card onto the table, saying “Delver”, and gets a Delver of Secrets from his box to represent it in play. Nemo calls for a judge and points out the issue with the checklist card. Nemo explains that he doesn’t think Amir should be severely penalized, and even offers to give Amir 4 Innistrad checklist cards so they can continue the match from here. What do you do?

Judges feel free to answer on Judge Apps!

Answer
Amir receives a Game Loss for Deck Problem, as his deck contained a card that wasn’t listed on his deck list. The penalty is a Game Loss because it was discovered by an opponent.