And my favourite, in a match between player A & B, someone playing a match next to them notices that player A has apparently stolen player B's goblin piledriver with a gilded drake. Problem is this happened two turns ago. So the judge is called over and rules that both players are to go back in time and redo the two turns! How cards in hand and board position was determined is anybody's guess but back in time they went anyways.
I was first call on this one, and bumped it up to the head judge.
It was obviously a mess.
What would you have done?
I'd have to look it up, but you should never back up turns -- especially to the point where a player knows what he or she will be drawing, or an opponent knows of specific spells in another player's hand.
Generally, you leave the game state as is. If the game has been affected too much by this, I believe (I'm guessing, I'll look it up later) at REL 3 it would be a game loss to the player playing the Drake, and a warning to the other player. (Both players are responsible for such things).
I was the one sitting next to the match who kinda noticed it. My opponent (dicemanx) was doing something -- tutoring or intuitioning -- and I happened to glance over at the game beside me. I saw the FCG player with a couple lands, and a lackey in play. His opponent (U/W I think -- I forget exactly -- I do know it had blue in it though) had a Goblin Piledriver and some land. I casually asked how he got the piledriver while glancing at the graveyards to see if I could see some effect. At this point, the FCG player remembers that the piledriver has Pro-Blue.
The blue player quickly checks the text on the Drake (as it was back in his hand at this time) and says it doesn't target. Myself and another person said that the Drake has a lot of errata, and they should call a judge to see if it does target (I was 98% certain it did). They did call the judge -- and after the head judge came over, I was rather shocked to see him reversing 2-3 turns worth of actions to set the game back to when the drake came into play.