What do you do?
Judges, feel free to discuss this scenario on Judge Apps!
AnswerThis is indeed an example of DEC, and by the new IPG, you should ask Arnold to reveal his hand to Naomi, and she should choose a card from it to be shuffled in an unknown part of Arnold’s library.
The action of Scry 1 was performed, incorrectly; once we fix the DEC, we aren’t going to back up and Scry again. (Doing so could create an advantage for Arnold.)
Arnold will receive a Warning for Drawing Extra Cards. Naomi should not receive a Warning for FtMGS, because she did not have reasonable time to point out the mistake or prevent Arnold from making it.