A situation similar to this came up in an event I was playing in yesterday, and I wanted to ask a followup related question:

Player A attempts to cast a spell with Affinity for Artifacts. However, Player A miscounts his Affinity and pays too much mana for his spell. Player B, his opponent, wanting Player A to tap extra mana for no reason to gain a strategic advantage, says nothing and allows play to continue. You, as a judge, are watching this game. Do you step in? If so, what do you do?

Followup question: Same situation as above, except instead of watching the game, you are called over by a spectator who notices Player A's mistake. What do you do?

Thanks.

Casting a spell with extra mana in Mana pool without announcing it is
violation of Comprehensive Rules:

CR 106.4a: If a player passes priority (see rule 116) while there is
mana in his or her mana pool, that
player announces what mana is there. If any mana remains in a player’s mana
pool after he or
she spends mana to pay a cost, that player announces what mana is still
there.

General violation of Comprehensive Rules is GRV:

IPG 2.5: This infraction covers the majority of game situations in
which a player makes an error or fails to follow a game
procedure correctly. It handles violations of the Comprehensive Rules that
are not covered by the other Game Play
Errors.

Therefore I would intervene in both cases mentioned above and issue GRV
Warning to Player A.

I would also investigate player B and provided that he knew about this rule
and purposely ignored it in order to gain advantage, he should be
disqualified. Otherwise he should receive FtMGS warning.

Provided that the game has not ended (because of disqualification) I would
also backup to the point of error and I would allow Player A to untap lands
which produced the unused mana.


2014-05-18 19:15 GMT+02:00 Lyle Waldman <

There's nothing wrong with a player tapping more lands than needed for a payment. That said, however, there is something wrong with paying the wrong amount of mana. When it comes down to this, the player's word choice and actions become relevant.

Say the player explicitly states “Pay 5 mana, cast spell X” when said spell's Affinity would make it 4. The player has committed a GRV by spending the incorrect mana payment. Likewise, if you determine the opponent knew the mana payment was incorrect, then an investigation would be in order to determine if the opponent knew that what he was doing was illegal.

We get to a different beast when we come to unclear communication between players, however. Say that I have the same 4-mana cost spell after Affinity. When it comes to paying the cost, I tap 5 Islands and say nothing else about payments. Nothing illegal has actually occurred at this point. By all technicalities, there would be 1 blue mana floating (although the casting player may not be aware of this fact).

So when it comes to stepping in, it comes very strongly to “you have to be there.” If you determine the GRV route occurred, step in, do the relevant backup, and have the player pay the correct mana (should he still decide to cast the spell. We won't force him to). If you determine that there is simply mana floating, stick around in case either player states something incorrect. (For instance, the opponent says, immediately after the spell is cast, “so you have no mana floating?” “Correct”).

Originally posted by David Záleský:

Provided that the game has not ended (because of disqualification) I would
also backup to the point of error and I would allow Player A to untap lands
which produced the unused mana.

I agree with everything David says before this. The remedy for GRV allows us to rewind to the point of the error, which in this case occurred when the player passed priority with mana floating in his pool without announcing it. I would rewind to the point where the player has priority with the spell on the stack and inform him that he has X mana floating. I would not allow the player to untap any lands he tapped for mana, because he would have done this either before or during the casting of the spell, which is clearly before he even has the opportunity to pass priority with mana floating (as he does not receive priority until the spell is cast in its entirety).

What about with standard devotion decks? People quite often tap Nykthos for obscenely large amounts of mana, say they tapped for 9, spend 3 of it to cast spell X. They haven't explicitly stated how much they have left, but very simple math tells us they have 6 left. Is this a problem?

What about when he says he spends 3 more on the next spell, without having mentioned floating mana?

Thats covered by the CR too:

106.4a … If any mana remains in a player’s mana pool after he or she spends mana to pay a cost, that player announces what mana is still there.

So technically the player has to announce that there is six mana (of the specific color) in the mana pool after he/she pay the cost for the spell. To me it sounds like we enter GPE-GRV territory here.

Originally posted by Olivier Jansen:

What about with standard devotion decks? People quite often tap Nykthos for obscenely large amounts of mana, say they tapped for 9, spend 3 of it to cast spell X. They haven't explicitly stated how much they have left, but very simple math tells us they have 6 left. Is this a problem?

What about when he says he spends 3 more on the next spell, without having mentioned floating mana?

Then we technically have a GPE:GRV for violating a rule most players aren't even aware of. We educate them (and the opponent) about the requirement to announce floating mana. We can back up to the point of the error (passing priority without announcing floating mana), in case it matters to the opponent.