I want to echo what Clint said, but also point out that Toolcraft Exemplar's trigger has an Intervening If… so assuming no preexisting artifacts AP wouldn't be able to flash in an artifact in response to the trigger because there would be no trigger to respond to.

Originally posted by Matt Marheine:

I want to echo what Clint said, but also point out that Toolcraft Exemplar's trigger has an Intervening If… so assuming no preexisting artifacts AP wouldn't be able to flash in an artifact in response to the trigger because there would be no trigger to respond to.

True there would be no trigger so they wouldn't get the pump from having an artifact, though they would still be allowed to flash in an artifact at beginning of combat. Here the problem would stem from them thinking that there is a trigger they can respond to, and that is a whole different issue, with it's own remedies.
But good spot :-)

@Clint and Matt -

Thanks for the reminder! I forgot that the Combat and Go shortcuts are no longer symmetrical and I was so embarrassed by my incorrect thinking that I deleted my post above.

Instead of trying to compare the 2 shortcuts to support my point, I'll reference the documents to support argument that this is being adjudicated incorrectly:

Originally posted by MTR 4.2:

If the active player passes priority with an empty stack during their second main phase, or uses a phrase such as “Go” or “Your Turn” at any time, the non-active player is assumed to be acting in the end step unless they are affecting how or whether an end of turn ability triggers. End of turn triggered abilities that do not target resolve after the non-active player passes priority.

Edited Russell Deutsch (June 9, 2018 09:57:44 AM)

Originally posted by Dan Collins:

It does not. That sentence applies to choices made when the ability is put on the stack, such as targets, this trigger has choices made on resolution.

Hi Dan, I'm a little bit confused here. Right after the sentence Justin quoted, the IPG says : “For example, if the ability instructs a player to sacrifice a creature, that player can't sacrifice a creature that wasn't on the battlefield when the ability should have triggered.”. This is a choice made on resolution, just like Teferi. Wouldn't that mean that while it's true, the player does get priority since the trigger would go back normally through the stack, he can't chose to untap lands that he tapped in response (since they weren't legal choices back then if the trigger resolved normally) ?

Originally posted by Russell Deutsch:

Instead of trying to compare the 2 shortcuts to support my point, I'll reference the documents to support argument that this is being adjudicated incorrectly:

Originally posted by MTR 4.2:

If the active player passes priority with an empty stack during their second main phase, or uses a phrase such as “Go” or “Your Turn” at any time, the non-active player is assumed to be acting in the end step unless they are affecting how or whether an end of turn ability triggers. End of turn triggered abilities that do not target resolve after the non-active player passes priority.

To me it also seems the shortcut applies. If AP activates Teferi's +1, then says “go”, then NAP passes priority too, it fits the shortcuts so the delayed trigger starts to resolve.

But if I understand correctly that's not current policy? Is it because delayed triggers are not “end of turn triggered abilities”? Can someone explain what the current way to handle that scenario is? ^^;

Originally posted by Toby Hazes:

But if I understand correctly that's not current policy?

Actually, our Policy supports what Russell has been saying - that if AP passes (says “Go” or…), and NAP passes, the trigger is resolving and neither player will get priority to tap lands before two lands are chosen to untap.

As I stated before, if it's a MISSED trigger, the remedy is to put the trigger on the stack - and both players get priority.

The scenario we seem to be discussing is NOT a missed trigger, although AP may have forgotten about it - and if so, they're likely “trapped” into having to choose two tapped lands that they don't really want to untap (e.g., their opponent's lands).

Originally posted by Russell Deutsch:

I do not believe AP should receive priority after saying “go”. If the opponent “catches” this in end-step with AP not having untapped lands, the trigger was forgotten, not missed; and AP has just passed priority with the trigger on the stack.

This is entirely correct; this is definitely NOT a Missed Trigger, it's either forgotten or resolved incorrectly. If it's resolved incorrectly, we rewind to the point of the error - which is when the ability is starting to resolve; no one gets priority, we just resolve it correctly.

It's only Missed if we move beyond the point where the Trigger should be resolving (typically, the opponent's turn).

d:^D