Originally posted by Bartłomiej Wieszok:

As a judges we aim to deliver consistent rulings along every tournaments. If we decide to back up in one of that situation and not in other, then we do not deliver consistent rulings. We can't anticipate what card or colour players would name. In my opinion, not performing backups is less detrimental for flow of the game “overall” in this situations.

If you want to not back up both the Doom Blade + Voice and Swords + Meddling Mage scenarios, then we're arguing the same point on consistency, but different outcomes.

Originally posted by Tyrone Phillips:

This has been an interesting discussion, for the record I'm on board with not backing up Swords + Mage, it seems we are rewarding AP too much for forgetting their card's ability.

Both players are responsible for the game state, and both AP and NAP forgot about it. We should be looking at getting the game back to where it should be (or deciding that by backing up, the game could be too different from where it is/should be), and not focusing on who benefits from the fix. Caveat: we need to be looking at who benefits from the fix when investigating as part of establishing/disproving Cheating.

In the rare event that this comes up (much less multiple times in a tournament), AP gets a penalty that can upgrade to a Game Loss, whereas NAP gets a penalty that doesn't upgrade.

Lets go to an extreme. AP casts Iona, passes the turn. NAP untaps and casts a Lightning Bolt. NAP controlled four mountains and it's game three, he has only played red spells. Apon investigating, AP says ‘Its obvious I chose red, I didn’t think I needed to say anything'

Do you rewind, or just let AP choose with the bolt on the stack?

This gets into player communication, so every opinion will be prefaced with “Based upon the results of my investigation” and “This won't apply to every situation, since previous communication between the players will matter a lot”. That also means that possible answers will be fairly narrow in application.

I'd pull NAP off to the side first and ask what they thought AP named with Iona. If both players believe that Iona named red, even if it wasn't verbally, then Iona named red, both players get a talk on “being clear” and “asking questions if you aren't sure”, and Lightning Bolt goes back (since it wasn't legally cast). Past that, it depends on what I believe happened.