What do you do?
Judges, feel free to discuss this scenario on Judge Apps!
[expand title=Answer]What we have here is a case of Game Play Error – Looking at Extra Cards. Nadine has seen the top card of Arnold’s library. This wasn’t intentional, but as the definition of LEC says, “this includes errors of dexterity.” Arnold was somewhat sloppy putting his card back on top of the library, but there is no infraction for that. Each player immediately called for a judge, so Arnold doesn’t need to worry about Failure to Maintain Game State.
So Nadine receives a Warning, but the question is what to do about card that she has now seen. The Additional Remedy of LEC tells us to “shuffle the randomized portion of the deck.” In this case, even though Nadine was not supposed to know the identity of the top card, it was not random. It may be tempting to try to implement some fix that negates the advantage that Nadine has gained. However, this type of creative solution is not supported by policy and should not be attempted. (It is slightly awkward that Nadine has gained an advantage by her error, but slight awkwardness is nowhere near grounds for deviation.) We leave the deck as-is, with the known card on top and have the players resume their match.[/expand]