Ok without reading the previous responses…

First it seems like that Wear is being cast in response to the ETB tigger. I will confirm that this is the case before proceeding. If it is, then A had no opportunity to imprint anything, and A should not have been able to cast brainstorm. If A already drew cards, then A receives a GPE: DEC and gets a game loss. If A didn't draw the cards, then we rewind to the point before A cast brainstorm (it returns to A's hand, the mox gets untapped, and A has the opportunity to recast Brainstorm with a different mana source). A then recieves a GPE: GRV and gets a warning. In both scenarios, N gets no penalty, and I remind A to play more carefully.

Originally posted by Richard Vo:

If A already drew cards, then A receives a GPE: DEC and gets a game loss.

What does the MIPG say about Game Play Error–Drawing Extra Cards? Isn't there an infraction just prior to drawing cards, specifically the Game Play Error–Game Rule Violation for having cast Brainstorm illegally?

Oh noes….

GPE:DEC - Definition - A player illegally puts one or more cards into his or her hand and, at the moment before he or she began the
instruction or action that put a card into his or her hand, no other Game Play Error or Communication Policy
Violation had been committed, and the error was not the result of resolving objects on the stack in an incorrect
order

I missed the italicized portion… So then we rewind in both situations and the only penalty is the warning for GPE: GRV. 3 randomly chosen cards will be returned to A's deck from A's hand and the deck will be randomized (except for known portions). I guess my question is now… do the 3 cards get returned even if the brainstorm was completely resolved (i.e. 2 other cards were put on top of A's library)? I think yes…. but it seems like a particularly sad outcome for A (even though A is completely at fault here).

Edit: Oh I know… the 2 cards on top are returned to A's hand before the 3 random cards are selected to be shuffled into the library…

Edited Richard Vo (April 15, 2014 10:33:42 PM)

GPE:GRV for Atari that comes with a warning and a backup to just before he tapped the mox. In theory I'd try to ignore Atari's question, but I'm only human and would probably ask them if the trigger is on the stack or not.

So here's the thing that's bugging me: I'm called over to a table to fix the mess that the players are in, and there's also an unacknowledged triggered ability that's on the stack. Do we, in the interest of making the original problem crystal clear, ask about the trigger (and in doing so inadvertently help the players to play better), or never acknowledge the trigger involved at all (and potentially make a mess of the actual infraction)?

Here's why not

Originally posted by IPG 2.1.:

Judges should not intervene in a missed trigger situation unless they intend to issue a Warning or have reason to suspect that the controller is intentionally missing his or her triggered abilities.

but does this actually apply here?

Richard Vo
Edit: Oh I know… the 2 cards on top are returned to A's hand before the 3 random cards are selected to be shuffled into the library…

Surely you mean put them on top of their deck, right?

Edited Alfred Bellinger (April 15, 2014 11:39:56 PM)

Originally posted by Richard Vo:

Oh noes….

I missed the italicized portion… So then we rewind in both situations and the only penalty is the warning for GPE: GRV. 3 randomly chosen cards will be returned to A's deck from A's hand and the deck will be randomized (except for known portions). I guess my question is now… do the 3 cards get returned even if the brainstorm was completely resolved (i.e. 2 other cards were put on top of A's library)? I think yes…. but it seems like a particularly sad outcome for A (even though A is completely at fault here).

Edit: Oh I know… the 2 cards on top are returned to A's hand before the 3 random cards are selected to be shuffled into the library…

Yep, your edit is totally correct. Whenever we do a backup, we undo every action in reverse order. Having him return those two cards to his hand is the easy part, compared to choosing 3 cards to put back on top.

Alfred: I think we're OK talking about the trigger. After all, the player did explicitly ask and we're already involved, we're not really “intervening”.

Edited Dan Collins (April 15, 2014 11:50:18 PM)

Thank you to everyone who took part in this week's Knowledge Pool scenario!

In our scenario, atari tapped her Chrome Mox before resolving the imprint triggered ability, which is perfectly legal. However, she cast Brainstorm as if it had made blue mana, when in fact it made no mana at all - and that's a Game Rule Violation, for which she should receive a Warning. Because Nintendo pointed out the error immediately, there should be no Failure to Maintain Game State Warning issued to him.

Now, there's the issue of a fix. The IPG gives us some direction:

If the error was discovered within a time frame in which a player could reasonably be expected to notice the error and the situation is simple enough to safely back up without too much disruption to the course of the game, the judge may get permission from the Head Judge to back up the game to the point of the error.

The point of error is casting Brainstorm without the mana to pay for it. Since nothing has happened since that action, we can easily back up by putting the Brainstorm back in Atari's hand. After the fix the gamestate looks like this: Wear // Tear is on the stack targeting the Chrome Mox, with the Imprint trigger underneath it. The head judge does have the option to leave the game state as is, but the situation in this case is simple enough that we recommend the rewind.

Thanks everyone for your continued participation, and we'll see you soon for another Knowledge Pool scenario!