Thanks for your responses this week! As many of you correctly identified, this is not one but two instances of a Deck/Decklist Problem. Both Adam and Nate have presented illegal decks; Nate because he has a Desecration Demon he shouldn’t have, and Adam because he only has 59 cards in his deck. Both players receive the prescribed game loss, and we fix the problem by returning the Demon to it’s rightful owner and double-checking that each player has only the cards they’re supposed to. Importantly, due to the recent update to the IPG, the two simultaneous game losses we just awarded do not count towards the reported match result. However, they should still be recorded as penalties on the match slip and by the scorekeeper.

A few of you mentioned a situation in which Adam presented a legal deck of 60+ cards for game two. This could happen either by Adam attempting to sideboard up to 61+ cards for game 2, or by him accidentally not sideboarding on a one-for-one basis. If that was indeed the case, and your investigation determines that Adam did not notice the missing card, then his D/DLP does not carry a game loss because the missing card was from his sideboard. The IPG says

Sideboards are considered to be a part of the deck for the purpose of this infraction. If sideboard cards are missing, make a note of this, but issue no penalty.

The IPG is telling us to adjust the decklist to reflect lost sideboard cards, but the card in question is not actually lost. We return the Demon to it’s owner, and issue Adam no penalty. Nate would then be awarded a game loss, which will affect the reported match results.