Originally posted by Colleen Nelson:

So even if we technically treat an O-Ring different from a Doomblade, the reality is most players don't.

Yes this is my opinion as well.

Players are naturally shortcutting an O-ring to work just like Doom Blade. And in normal gameflow they are the same, but technically they're different, so if it needs to be rewound, the O-ring is still cast.

Players are naturally shortcutting Arbor Elf to work just like Elvish Mystic. And in normal gameflow they are the same, but technically they're different, so if it needs to be rewound, the Arbor Elf remains tapped.

Edited Toby Hazes (July 30, 2013 05:22:39 PM)

Michel, should the fix really depend on what might happen or what an opponent might be holding?

If the elves were tapped before announcement, then it was a perfectly legal action. Our job is to undo illegal actions, not stupid ones. For Regular, I can definitely see unwinding. But if you're in a big Comp event, I think unwinding could be viewed as bending the rules for the caster. Also, I thought the explanation of “mana produced for the spell” was only for the mana that was made during the announcement. Maybe that's just thinking too literally?

Originally posted by Ashley Puhlman:

If the elves were tapped before announcement, then it was a perfectly legal action. Our job is to undo illegal actions, not stupid ones. For Regular, I can definitely see unwinding. But if you're in a big Comp event, I think unwinding could be viewed as bending the rules for the caster. Also, I thought the explanation of “mana produced for the spell” was only for the mana that was made during the announcement. Maybe that's just thinking too literally?

Unlike Elvish Mystic, our latest mana Elf, Arbor Elf does not have a mana ability. Arbor Elf does have a normal activated ability that uses the stack, can be responded to, and can't be activated during the process of casting a spell.

That does certainly merit some thought as to how you approach the situation. Especially at Competitive REL, where we do have certain expectations regarding rules knowledge, shortcuts nonwithstanding.

601.2 describes the order of casting a spell.
A. Announce the spell.
B. Choose a mode.
C. Announce all targets.
D. Announce the distribution of counters/damage (ie Fireball)
E. Total cost is determined.
F. Activate mana abilities to pay for sepll.
G. Pay all costs for the spell.

601.2 also says if, at any point during the casting of a spell, a player is unable to comply with any of the steps listed below(now above), the casting of the spell is illegal; the game returns to the moment before that spell started to be cast.

Nowhere in steps A-G, allow for activation of non-mana abilities to pay for the spell and these must have happened before the casting of the spell. So if we return to the “moment before the spell started to be cast”, this would be after the activation of the 2 Arbor Elves ability.

With the O-Ring, since it doesn't need a target when casting the spell would resolve and then the ETB ability would need a legal target and if the player tries to target an illegal target, we rewind to before the ETB ability goes on the stack, which is after the spell resolved.

With Doom Blade, since Step C would be illegal if targeting a black Creature, then we rewind the spell.

I believe the O-Ring and Doom Blade illegal targeting would come with GRV + warning.

I'm sorry, I was going with the elves being tapped before the announcement, I must have misunderstood.

Why do we allow players to untap their mana sources when applying a fix for illegally casting a spell or activating an ability, even is tapping their mana sources is, by itself, a perfectly legal play?
My understanding is that, in case of rules mistakes, we want to fix the game in the most organically way possible, and leave the game state as close as possible as it was before the core mistake happened.

Brian rightfully points out the differences between taping Arbor Elf and Elvish Mystic in order to get additional manas. However, I don't have the feeling that, in most games, this differences are actually strategically or tactically relevant - especially if the opponent didn't mention any intent to react to as such ability.
As such, treating them differently has some merit, but this merit have to be balanced again the possibility of correcting the post-mistake game state in a cleaner way.

So while the by the book fix for GRV doesn't seem to apply to Arbor Elf, I think it should, and I'd prefer to have them untaped.

I would not consider O-Ring and Arbor Elf to be similar situations. With O-Ring, the spell is cast, the opponent has the opportunity to respond, thereby giving the active player information, and then the spell resolves.

I'm hard pressed to come up with a situation (in standard anyway) where using an Arbor Elf to untap a forest results in gaining any information or having any other noticeable impact on the game state.

I think the goal of our fix in this situation should be to restore the game state to where it was before the illegal action as a whole began. Not draw the line on a technicality. I certainly admit I could be wrong on this.

It is an interesting question though.

I agree with the intent of untapping the elves. I see the logic, and it feels nicer overall. My only concern is this - consistency and where to draw the line. There are a lot of ways to add mana to your mana pool. Which methods would you give back and which wouldn't you give back? Today you let a player untap their arbor elf. What happens if the next player sacrificed a lotus, or if the next player cast a spell to add mana? I think forcing the elves to remain tapped does seem too technical, but I think if I allowed an untap I would be thinking in the back of my mind “did I just open a can of worms?”

The “can of worms” can only open so wide, luckily. The Comp Rules include guidance on how to handle the more unusual mana abilities that cause cards to change zones.

717.1. If a player realizes that he or she can’t legally take an action after starting to do so, the entire action is reversed and any payments already made are canceled. No abilities trigger and no effects apply as a result of an undone action. If the action was casting a spell, the spell returns to the zone it came from. The player may also reverse any legal mana abilities activated while making the illegal play, unless mana from them or from any triggered mana abilities they triggered was spent on another mana ability that wasn’t reversed. Players may not reverse actions that moved cards to a library, moved cards from a library to any zone other than the stack, or caused a library to be shuffled.

Originally posted by Josh Stansfield:

The “can of worms” can only open so wide, luckily. The Comp Rules include guidance on how to handle the more unusual mana abilities that cause cards to change zones.

717.1. If a player realizes that he or she can’t legally take an action after starting to do so, the entire action is reversed and any payments already made are canceled. No abilities trigger and no effects apply as a result of an undone action. If the action was casting a spell, the spell returns to the zone it came from. The player may also reverse any legal mana abilities activated while making the illegal play, unless mana from them or from any triggered mana abilities they triggered was spent on another mana ability that wasn’t reversed. Players may not reverse actions that moved cards to a library, moved cards from a library to any zone other than the stack, or caused a library to be shuffled.

But this is not clear on whether or not the activated ability of the Arbor Elf can be reversed. Is it?

Originally posted by Frank Rodriguez:

But this is not clear on whether or not the activated ability of the Arbor Elf can be reversed. Is it?

No it is not clear about that, and that's what everyone is discussing in this thread. I was just trying to show that there isn't exactly a slippery slope to worry about here if one does decide to allow the Arbor Elves to be rewound.

So both 1) Rewinding the elves and 2) keeping them tapped are both correct even if they go through the steps explicitly?;

Originally posted by Ashley Pullman:

Michel, should the fix really depend on what might happen or what an opponent might be holding?

Since I decide to rewind the untapping of the arbor elves as if they were mana abilities activated for Trostani, I don't rewind them if they were not activated solely as mana abilities for Trostani. So the fix depends on why the active player explicitly activated them before announcing the spell.

In addition of Sebastian's comment about the fact that if one is a shortcut of the other, making any difference of treatment is quite hard to justify, having the fix changing if the player tap them during the casting of a spell, or do the precisely correct play and tap them before casting the spell, is likely to be perceived as a punishment of technically correct play. That's not really coherent with the message we usualy wants to send toward players.

to all the people who are worried about punishing technically correct play
of the arbor elf player: he just cast trostani for GGGGW. this player is
not playing technically correctly.