Hello all.
IPG 2.1 says

A triggered ability that causes a change in the visible game state or requires a choice upon resolution: The controller must take the appropriate physical action or acknowledge the specific trigger before taking any game actions that can be taken only after the triggered ability should have resolved.

Later, it says

a player demonstrating awareness of an optional trigger with no visible effect is assumed to have made the affirmative choice unless the opponent responds.

Scenario a) Adam controls an Eldrazi Mimic, casts and resolves a Reality Smasher and says “Trigger”. Norman has no response to the trigger, Adam says nothing about the choice he takes and declares atackers. According to MIPG it is assumed that he chooses the Mimic to be a 5/5, because the opponent did not respond. Am I right?

Scenario b) Adam controls an Eldrazi Mimic, casts and resolves a Reality Smasher and says “Trigger”. Norman responds to Mimic's ability casting a Dismember on the Smasher, Adam says nothing about the choice and declares atackers. According to the MIPG, it is assumed that he chooses the Mimic NOT TO BE a 0/0, because the opponent responded. Am I right?

Scenario c) (my concern). Adam controls an Eldrazi Mimic, casts and resolves a Reality Smasher and says “Trigger”. Norman respondes to the trigger casting boros charm (for example) choosing to deal 4 damage to Adam. Boros Charm resolves and Adam says nothing about the choice and declares atackers. Is it still assumed that Adam chooses the Mimic NOT TO BE a 5/5 because the opponent did respond?

Thank you very much for your help.
Cheers,
Javier.

Edited Javier Martin Arjona (Oct. 11, 2016 04:35:44 PM)

Yes, I believe all three of your situations are correct.

Originally posted by Javier Martin Arjona:

Scenario c) (my concern). Adam controls an Eldrazi Mimic, casts and resolves a Reality Smasher and says “Trigger”. Norman respondes to the trigger casting boros charm (for example) choosing to deal 4 damage to Adam. Boros Charm resolves and Adam says nothing about the choice and declares atackers. Is it still assumed that Adam chooses the Mimic NOT TO BE a 5/5 because the opponent did respond?

I don't believe the intent of the “unless an opponent responds” line is to dagger players when the opponent responds in ways that aren't relevant to the trigger (like this boros charm example).
If the situation played out like this:
Adam: “Trigger”
Norman: “Boros Charm you in response”
Adam: “Ok, I take four. Attacks?”
Norman: “Sure”
Adam: “Attack for 10”
it sounds to me like Adam has done everything he could reasonably be expected to do. He announced his trigger, and he hit the last note of the missed trigger section: he made the “change known by the first time the change has an effect on the visible game state.”

So in the other thread on this topic, Dan Collins responded and I now think that my answer was incorrect.

Nothing in the IPG implies that the active player even defaults to choosing “no.” The IPG says that “yes” is the default choice under certain circumstances; it also says that the trigger can be *missed* under certain circumstances.

If the trigger is clearly acknowledged, but a choice is not clearly made, we're dealing with a communication issue or possibly a Game Rule Violation–not a default choice or a missed trigger.

Originally posted by Javier Martin Arjona:

(a) … because the opponent did respond

I believe you meant “because the opponent did NOT respond”; if so, then that is correct. (And if that's not what you meant, then … well, I don't understand the question.)

Originally posted by Javier Martin Arjona:

(b) … According to the MIPG, it is assumed

Nope, the MIPG doesn't specify a default assumption when an opponent does respond. However, according to obvious visual clues and common sense, he clearly chose not to have his Mimic copy a 0/0 creature's P/T. ;)

Originally posted by Javier Martin Arjona:

© Norman respondes to the trigger casting boros charm (for example)

umm… let me know when irrelevant corner cases like this actually happen. Or, don't, because it's still largely irrelevant.

I interpret this phrase

MIPG
assumed to have made the affirmative choice unless the opponent responds

to mean unless the opponent responds to that trigger. Any other interpretation renders this somewhat vague, and that's not how the policy team works. Yes, there is an economy of words - necessary to maintain a workable document - but the words are carefully chosen by masters of proper English syntax. Reading too much into any wording, or - as in this case, in my opinion, reading it “sideways” - can destroy meaning.

d:^D

Edited Scott Marshall (Oct. 11, 2016 12:40:32 PM)