Andrew and Nina are playing at a PTQ.
Andrew has 2 Forests, a Plains, and 2 Arbor Elves in play. Taps both Arbor Elves and all 3 lands and announces “Trostani, Selesnya's Voice”. Nina looks at Andrew's board and realizes that he cannot generate 2 White mana, and immediately call's for a Judge.
What is the proper penalty and where do you rewind the game to?

It's a GRV + Warning for Andrew, because he attempted to cast a spell without legally paying for it. Back up to before the casting of the spell, Trostani goes back to Andrew's hand, lands and elves are untapped, play continues. No penalties to Nina, because she called attention to the error immediately.

Edited Colleen Nelson (July 29, 2013 10:33:00 PM)

I might add that although tapping those Arbor Elves is technically legal, we also rewind that. It's directly connected to trying to cast Trostani. Assumption is also no bad intent by Andrew.

But shouldn't the Arbor Elves remain tapped and Andrew have 2 Green Mana floating? If Nina accepted the shortcut of tapping his 2 Arbor Elves to mean : 1) Tap a Forest to float a Green. Tap Arbor Elf to Untap a Forest. Priority passes to Nina and then back to Andrew. 2) Tap a Forest to float a Green. Tap Arbor Elf to Untap a Forest. Priority passes to Nina and then back to Andrew. 3) Cast Trostani, Selesnya's Voice with tapping a Plains, and 2 Forest.

I could see this if it was Mysitc Elf, because thier ability is a Mana Ability. Arbor Elf's ability is not a Mana Ability. You are not allowed to activate non-Mana abilities to pay for a spell.

I agree with Frank here. At Regular, I'm all for rewinding the Arbor Elves as well, but at competitive, I expect a higher level of play, and the knowledge that Arbor Elf cannot be used during the casting of a spell.

Since it isn't totally clear from the OP, let's consider two slightly different situations:
1.) Andrew taps two Forests, then taps his two Arbor Elves to untap the Forests, then lays down Trostani, announces it, and proceeds to tap his Forests again and tap his Plains. Nina calls for a judge.
2. Andrew lays down Trostani, announces it, and taps his two Forests, his two Arbor Elves, and his Plains. Nina calls for a judge.

In a REL Competitive tournament, would you treat these differently? Why or why not?

We're supposed to rewind to the point immediate before the error. In this case, I think a quick investigation would reveal the first error was tapping the Arbor Elf thinking that it produced white mana. (ie, Andrew was thinking of Avacyn's Pilgrim")

I'm trying not to invent an alternate scenario, but it did say they tapped the creatures first, rather than tapping land then creatures.

at competitive, I expect a higher level of play, and the knowledge that Arbor Elf cannot be used during the casting of a spell.

This seems all well and good, but, does this mean you'd given someone a GRV if they tapped a forest and an Arbor Elf after announcing say, a Kalonian Tusker? It seems to me tapping Arbor Elf in a scenario like this is implicitly shortcutting the “tap land, tap elf, untap land, tap land” sequence. If the opponent never objects to it, I see absolutely no issue.

1.) Andrew taps two Forests, then taps his two Arbor Elves to untap the Forests, then lays down Trostani, announces it, and proceeds to tap his Forests again and tap his Plains. Nina calls for a judge.
2.) Andrew lays down Trostani, announces it, and taps his two Forests, his two Arbor Elves, and his Plains. Nina calls for a judge.

As much as I hate to say it, I think we have to treat these scenarios differently. As mentioned before, tapping the Arbor Elves to pay for something is effectively shortcutting. In the 2nd scenario the block of actions is interrupted, and as such, Andrew shouldn't be held to anything in the action block past the point of interruption. However in the first scenario no such short or block of actions existed; he clearly took the steps one at a time, and resolved the Arbor Elf abilities before announcing the Trostani. As far as how this relates to the original scenario? The original scenario, to me, read like a block of actions: he tapped all the stuff to pay for Trostani all at once and tried to cast Trostani. Hence why I'd be ok with backing up the mana elves in the original scenario.

Edited Colleen Nelson (July 30, 2013 12:08:07 AM)

Originally posted by Sebastian Reinfeldt:

Since it isn't totally clear from the OP, let's consider two slightly different situations:
1.) Andrew taps two Forests, then taps his two Arbor Elves to untap the Forests, then lays down Trostani, announces it, and proceeds to tap his Forests again and tap his Plains. Nina calls for a judge.
2. Andrew lays down Trostani, announces it, and taps his two Forests, his two Arbor Elves, and his Plains. Nina calls for a judge.

In a REL Competitive tournament, would you treat these differently? Why or why not?

I think these are the same situation. 2 is just short cutting, and if both players are agree to what really happened, then we should assume 1 is what happened.

Originally posted by Colleen Nelson:

As much as I hate to say it, I think we have to treat these scenarios differently. As mentioned before, tapping the Arbor Elves to pay for something is effectively shortcutting. In the 2nd scenario the block of actions is interrupted, and as such, Andrew shouldn't be held to anything in the action block past the point of interruption. However in the first scenario no such short or block of actions existed; he clearly took the steps one at a time, and resolved the Arbor Elf abilities before announcing the Trostani.

But if variant 2. is just a shortcut for variant 1., then why should they be treated differently?

For those who rewind the tapping of the Elves, would you also entirely rewind casting Oblivion Ring/evoked Shriekmaw with a wrong target for the EtB trigger, or are those different?

Edited Toby Hazes (July 30, 2013 08:57:20 AM)

Yes that is different Toby. If you cast a spell you need legal targets for it to simply be able to cast it. If however you cast a spell that has an ETB trigger associated with and you don't have targets for that trigger, that would be considered though luck. If somebody chooses an illegal target for the ETB trigger than you rewind to the moment the trigger is about to come on the stack.

So if Arnold casts Shriekmaw and his opponent only has black creatures, than there is a big possiblity that Arnold will have to choose one of his own creatures to destroy.

Technically speaking, tapping arbor elf isn't a mana ability. However, in all normal gameplay, even at competitive, players will treat it as if it is. In the situation of the OP this is clear, because the player taps them when he would normally activate mana abilities. I definately would rewind in this situation, because the philosophy in the situation is exactly the same as if a mana ability had been activated (even though the situation is different from a technical rules perspective).

If the active player explicitly activates his arbor elves before announcing the spell, I'll probably ask a few questions. I don't want to punish a player for trying to play correctly, so if his reason for doing that is to play technically correct, I'll still rewind, using the same philosophy of undoing all mana payments made for the spell. However, if for some reason the order of things happening is relevant (for example, the active player suspects his opponent has instant speed land destruction) and the actions couldn't be shortcutted for that reason, the activation of the arbor elves wouldn't be rewinded, because in that situation their activation and the casting of the spell have become seperate events.

In the last situation, keep an eye out for cheating, because a player might be trying to intentionally cast an illegal spell with the intention of untapping his arbor elves.

Also, let's be honest, if a player said “O-Ring your Geist of St. Traft”, chances are what's going to happen half the time is the opponent will say “you can't do that”, the first player will say “oh nevermind”, untap his mana, put the O-Ring back in his hand, with nothing else being said of it. So even if we technically treat an O-Ring different from a Doomblade, the reality is most players don't. At Regular REL I would indeed let an entire O-Ring be re-wound. At Comp REL, well, if I was specifically called in that scenario, then yes they only get to rewind to the trigger targeting choice if that's what the rules specify.

Originally posted by Colleen Nelson:

Also, let's be honest, if a player said “O-Ring your Geist of St. Traft”, chances are what's going to happen half the time is the opponent will say “you can't do that”, the first player will say “oh nevermind”, untap his mana, put the O-Ring back in his hand, with nothing else being said of it. So even if we technically treat an O-Ring different from a Doomblade, the reality is most players don't. At Regular REL I would indeed let an entire O-Ring be re-wound. At Comp REL, well, if I was specifically called in that scenario, then yes they only get to rewind to the trigger targeting choice if that's what the rules specify.

I don't know about that. I've seen a bunch of players try to force opponents to doom blade their own creature if there was nothing else for the spell to target or for the spell to just “fizzle.”

If I was there and had to rule, I would say untap everything and GRV + Warning for Andrew. If something was said about the elfs shouldn't untap I would explain that the elfs shouldn't have been tapped during the announcement of the spell anyway and that was part of the rewind.