This situation came up at a recent PTQ and I am wondering what other judges opinions are.

Alex is playing against Naomi and Alex has the ‘Mindslaver Lock.’ Alex had control of Naomi's last turn and cracked a fetchland allowing Alex to see that Naomi has no effects in deck that could prevent Alex from milling Naomi out (Eldrazi-type effects or the like). Naomi has 7 cards in hand so Alex proposes a shortcut where on each of his own turns he will execute the Lock and pass turn. Then on Naomi's turn Alex is going to draw, tap all of Naomi's land, and then discard whatever was drawn for that turn. Alex is going to repeat these actions until Naomi loses (no cards in library). Naomi declines the shortcut saying “play it out.” Alex calls you over asking if Naomi is allowed to do this. It is game 3 with very little time left in the round.

Note: The rules for shortcuts are in both the MTR (4.2) and the CR (716).

“I don't want to lose” is no more a valid reason to reject a shortcut or loop proposal than “it's such nice weather outside” or “I had eggs for breakfast”.

Alex proposed a shortcut. Naomi can either accept it, or shorten it to some point where she wishes to deviate from the proposal. If she doesn't want to deviate (as in your situation, where she cannot), she'll have to accept the proposal.

That is perfectly acceptable. The rules for new tournament shortcuts in MTR 4.2 indicate that a player has the right to request the use of a new shortcut, not that they can unilaterally declare that they are doing so:

Originally posted by MTR4.2:

(…) if a player wishes to demonstrate
or use a new tournament shortcut entailing any number of priority passes, he or she must be clear where the game
state will end up as part of the request.

As such, I think N is perfectly within her rights to decline the use of the shortcut. Provided she continues to play the game at a reasonable pace, then there can be no question of stalling or slow play. Taking advantage of the round clock in this manner is an acceptable, if not entirely sporting strategy.

I'd probably ask Naomi, away from the table, at what point in Alex's shortcut she intended to interrupt it. As we know from the MTR:

Originally posted by MTR 4.2:

A player may interrupt a tournament shortcut by explaining how he or she is deviating from it or at which point in the middle he or she wishes to take an action (…) A player may not request priority and take no action with it.

If Naomi says that she just wants to see if Alex forgets to put his Mindslaver back on top, or something like that, I would allow the shortcut. Alex has demonstrated understanding of his sequence, and we don't make the Splinter Twin player tap and untap 1,000,000 times because he might untap the wrong Pestermite at one point.

If Naomi says that she has a card in her deck that would allow her to break the lock, (I can't think of one, but let's assume that Naomi names a valid card), I'd remind Naomi about the penalty for Stalling and ask them to play it out. I'd stay very close to the table to watch for Stalling - it's unlikely that Naomi will commit Slow Play unintentionally, since she literally can't make any choices during her turn, so any “in the tank” thinking time is going to make me very suspicious.

Edit

Robert Hinrichsen
That is perfectly acceptable. The rules for new tournament shortcuts in MTR 4.2 indicate that a player has the right to request the use of a new shortcut, not that they can unilaterally declare that they are doing so:

Robert, remember what CR 716 has to say here:

CR 716
716.2b. Each other player, in turn order starting after the player who suggested the shortcut, may either accept the proposed sequence, or shorten it by naming a place where he or she will make a game choice that’s different than what’s been proposed. (…)

716.2c. Once the last player has either accepted or shortened the shortcut proposal, the shortcut is taken.

Your options when a player proposes a shortcut are to accept it or modify it - simply rejecting it isn't on the menu.

Edited John Brian McCarthy (Aug. 6, 2014 09:14:51 AM)

Originally posted by Robert Hinrichsen:

if a player wishes to demonstrate or use a new tournament shortcut entailing any number of priority passes, he or she must be clear where the game state will end up as part of the request.

But just a few sentences later, we have “A player may not request priority and take no action with it.” If the Mindslaver lock doesn't allow that player to take any actions during the shortcut, how can it be legally interrupted? The use of the word “request” doesn't necessarily give a player completely free reign to deny it.

Edited Michael Shiver (Aug. 6, 2014 09:14:09 AM)

I was just discussing this situation this weekend. Taking a look at the comprehensive rules 716.2b looks to me like it says that when presented with a shortcut to handle a loop, your options are:
1) Accept the shortcut as proposed; or
2) Shorten the shortcut by declaring a place where you will act to interrupt the loop.

I don't see, “Make your opponent play out all of the iterations so they use up the clock” as an option.

Also, looking at the discussion in the immediately preceding thread here http://apps.magicjudges.org/forum/topic/11670/ regarding how to handle other infinite loops, this situation seems pretty similar to the loops discussed. If we would allow someone to demonstrate infinite scry 2 and simply reorder their library to suit, how would we not allow someone to demonstrate the Mindslaver lock and skip to their opponent drawing off an empty library?

Yeah, this seems like a pretty clear case of demonstrating a loop and repeating it until Naomi gets milled out. Naomi isn't going to interrupt it, so … yeah.

So my follow-up here is how does this situation change if Alex does not know the contents of Naomi's deck? Would you still allow the shortcut if there is the chance that Emrakul is in Naomi's deck?

If Naomi can offer a valid reason why the proposed loop will fail, at some point, then we have to respect that. Given the scenario as posed, she can either accept the loop as proposed or suggest a smaller number of iterations before she'll act. (And yes, she has to be able to act!)

d:^D

If Emrakul gets drawn during a given turn then Alex is going to Make Naomi discard something else during that iteration, and a player is allowed to interrupt his or her own shortcut. However, you do bring up an interesting point regarding the fact that loops can't have conditional actions. In this case, I think you should take John McCarthy's earlier advice and ask Naomi away from the table whether she has a valid reason to reject the shortcut.

Originally posted by Scott Marshall:

If Naomi can offer a valid reason why the proposed loop will fail, at some point, then we have to respect that. Given the scenario as posed, she can either accept the loop as proposed or suggest a smaller number of iterations before she'll act. (And yes, she has to be able to act!)

d:^D

The obvious follow-up seems to be “What if Alex hasn't seen Naomi's decklist?”

It seems like Alex could still propose the shortcut, and Naomi would still have to offer up a point where she would deviate (presumably by talking with a judge away from the table). If her only interaction is “I'm going to exile Simian Spirit Guide to make Red during Alex's turn.” then I'd be unimpressed.

If the interaction was “I'm going to hope that Alex doesn't exile any Simian Spirit Guides, or cast any Lightning Bolts that I draw. If he doesn't, I'm going to Bolt him during his upkeep. He's at 2.” we'd be in a harrier spot.

My solution would probably be to have Alex take Naomi's turns one at a time, and assume that his own turn is completely shortcutted, and that Naomi's turn is shortcutted to draw, tap all lands, discard. He could then draw/discard as quickly as he was physically able to manipulate the cards, and if Naomi ever had a chance to take a game action (other using the Magic Store & Event Locator at Wizards.com/Locator to find tournaments in her area), she could interrupt at that time.

I'm not sure if it would be too much assistance to help define that shortcut for Alex, but if he'd already proposed something fairly similar, I'd be fine tweaking it into something workable.