This knowledge pool situation is quite interesting, in that on its surface it appears to be a “do we game loss,” but in reality it is a philosophy and investigation question.

To answer the main question, let me propose my own - what infraction did the player commit? Deck, TE - Deck List Problem? Sure, he presented a deck with missing cards, and he potentially gained advantage from the action. . The game where the advantage “may” have been had has been done, and win or lose, the game which we would want to game loss him is over. We would not apply the game loss to the next game, because at this point, the advantage has been corrected for game 2. This is functionally different from TE - DLP, in that in that situation the problem revolves around the deck list , and the advantage is ongoing.

Quick Answer - A simple - try to be more careful next time -, and some instruction on preventing the problem in the future.

There is another angle that this situation needs to be looked at through, and that is the “why did the player call me, to let me know about this problem.” There are three types of players generally (in this situation), the one that genuinely feels like he did something wrong, and wants to fix it “I should have lost the game,” the one that if afraid of being DQed, and calls, and the one who hides it to try and avoid a penalty altogether. The way we figure out which type of play we are dealing with is to talk to the player (away from the table, standing right by the table should be fine). In the end, we are looking for signs he is cheating. Normally a question like “how did you find out, or why did you call a judge,” are good questions. The point is, in my own experience we rarely find cheaters calling a judge on themselves in this situation.

I actually had this almost exact situation happen to me at day 2 GP Sydney where the player pointed out that he had failed to de sideboard from his previous game. From a few question I deduced that he felt that even though he knew what he accidentally did was not right, he felt that he should tell a judge so that his conscience is clear and that's how the game should be played.

My initial reaction was D/DLP but after a chat with a higher level judge, in this case was Jeff Morrow, I realized that what happened did not fit the infraction. I thanked the player for calling a judge on himself and reminded him to remember to de sideboard and let them continue the match. His opponent agreed with the ruling and play went on.
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Here's another question:

Does a player commit an infraction if he or she does NOT call a judge in these cases?

As others have mentioned after a few questions to the player: “When did you first notice?” and “Did you have any opportunity to search your deck during the first game?”.

Pending their responses I may ask more questions (if they answer yes to searching their deck for example). Otherwise if i feel this is an honest mistake and their is no underhanded activity i thank the player for their honesty and instruct them to be more careful in further situations. While not officially handing out a warning for it I also feel like it this is something that should be noted down in WER just in case it comes up again with the same player that we have a log of it.

I think we're all in agreement that this would be a GL had the player discovered it at some point during the game (after mulligan decisions). It also seems that the judges are roughly in agreement that asking the player when/how this was discovered would be a good way to uncover cheating.

However, I differ from my colleagues on one point – a game loss penalty MUST be issued. This would just override the first game, so there would be no functional difference to the players. Nathan is still playing from a game behind in game two – EXCEPT the Deck/Decklist Problem will be recorded by the scorekeeper. Nathan should be commended for his honesty, and the solution I offer would have no functional difference on his record if he really is an honest player. However, if Nathan leaves a trail of these mistakes that “luckily” work to his advantage then the DCI should be made aware of this. I don't want to use names, but there were cases of players whose mistakes always seemed to help them and it was only through the vigilance of judges and the DCI that they were caught.

Lastly, this infraction is not a caution, and there is no option for a floor judge to downgrade the penalty.

Edited Sam Nathanson (April 15, 2013 05:17:50 PM)

@Samuel: So if the player had won the game you wouldn't give a game loss? Or you would apply it to the next game? Why are you so sure the GL MUST be given? Let's compare this to something that happens all the time:
A player comes to you and says: “Hi judge in the last round this and this happened in my match, is that correct?”
You: "No, that's not how it works, "
You don't give a GRV warning for that do you?

aside: I have given a GL for a similar situation, and still feel that was wrong.

The thing is not if you give a Game Loss for the infraction, because indeed, no you don't. But if through questioning you find out the player actually knew halfway the first game he is now actually cheating, because he failed to call a judge when he found out.

@Kenny: You're right, I neglected to answer the full question.

Had Nathan won the first game, I would've made it a game loss (with permission of the head judge as this is a cut above your typical D/DL). He won with a deck that was not legal and I doubt anyone would consider that “fair.” Yes, there is a limit to when we can issue these penalties – if this comes out three rounds later then I would not retroactively issue game losses, but that's not the scenario at hand. To me it seems like the only way this would get revealed much later is if the player were actively hiding the information for an advantage, which is a disqualification.

Kenny, you raise a good point about the retroactive warnings, but there are a few reasons we don't go back in that scenario:
1. You didn't see it and there's no opponent to confirm it. The player could be lying or mistaken.
2. It would be logistically difficult. The scorekeeper has enough on his/her mind without having to dig out a results slip for you and altering it.
3. A warning is not a GL. They are different penalties with different implications.

However, in the knowledge pool scenario presented here, we have an easily accessible slip, with a clear indication of what happened.

I also would like to point out that I'm not “so sure,” I have been mistaken before and I don't think it'll be too long before it happens again. ;)

Thanks to everyone that participated in this discussion. A lot of great points were brought up about this scenario.

There is no penalty to apply here, unless our investigation questions lead us to believe that cheating was involved. We need to ask questions to find out when Nathan discovered that the deck was 6 cards short, such as: “When did you notice the deck didn't contain 60 cards?” “Was it during the game?” “Did you purposely ‘forget’ to add the cards back in?” The fact that he called over the judge and the fact that the deck was short, as opposed to containing sideboard cards, probably means that this was not USC-Cheating. Another important question is to ask Nathan's opponent if he noticed that the deck presented contained less than 60 cards.

We do not assign a Game Loss for TE-D/DL. To put it simply, there is no infraction at the time the judge is called over. The game has ended. We won't give a game loss for something unverifiable. Had either player noticed this during the game, Nathan would have gotten a game loss for that game. We don't apply this to the next game he'd play like we do with a Decklist error. Decklist errors will always result in the Game Loss penalty being assigned, either to the current game or to the next game if we are between rounds. A Deck error only applies during an active game. We have no way of verifying that the game was played with an illegal deck. This is why you should never swoop for a deck check before the players have presented. If they haven't presented, they haven't yet committed an infraction, and we aren't serving the integrity of the tournament by premature swooping.

We instruct the players to continue onto game 2 and advise them to make sure they have legal decks when they present for game 2. Remind the players that counting their sideboards and presenting them before every game would prevent this situation. Presenting the sideboard (face down) is required by the MTR (3.15)

This answer is the same, regardless of the result of Game 1.

This exact scenario happened to me when i was playing in an event. I noticed my sideboard was too big after game 1 and called a judge on myself. I explained to the judge I had noticed my sideboard had mainboard cards left in it from the previous round. I explained I noticed the error as soon as I checked my sideboard. I was not given an infraction, but I was instructed to be careful in the future.
There are three main reasons I called for a judge at this time: 1. I knew the deck I had presented in game 1 could not have been legal; 2. I did not know the proper method for handling this situation and wanted to know how to do so in case I was called to handle a similar issue; 3. most importantly, I wanted to set an example, even if i would get a game loss or worse. I feel a player should call a judge if he has any question about a ruling or something that may jeopardize the tournament integrity. Assuming another player saw me call a judge on myself and overheard the conversation, he may be more inclined to do so in the future as well. We should not be suspicious of someone who calls a judge on him/herself, rather we should encourage it. If players are more willing to point out their mistakes and flaws, tournaments can run more smoothly and maintain more integrity.

I do apologize for the wall of text and I hope you find this post useful.