Split Second and Priority passing

[Nazdakka]

Another one of my judgement call style questions. I think I know what the answer is, but I'm curious to know what everyone else's view is.

It's the beginning of Player A's turn, and he controls a Mindslaver. Player A moves through his untap, upkeep and draw steps without incident. He then goes to his mainphase and pauses. Player B interupts A's thinking to cast Krosan Grip targetting the Slaver. A tells B that he can't do that, because he hadn't passed priority, and immediately annouces that he will activate the Slaver targetting B. B argues that this isn't on, and that A is abusing the timing rules.

Now, as I see it, A's view is essentially right - he didn't pass priority, and so B was wrong to jump in. However, I'm asking the question to get a view on the various priority issues surrounding Split Second and how this sort of problem should be dealt with. I can conceive of situations where the priortity situation is muddier, and A could start abusing the lack of an explicit pass of priority to gain an advantage.

What do people think?


Wordings
Krosan Grip
2G
Instant
Split second
Destroy target artifact or enchantment.

Mindslaver
6
Legendary Artifact
4, T, Sacrifice Mindslaver: You control target player's next turn.

[Godder]

When Player A goes to draw a card for the turn, that would be an excellent point to play Krosan Grip, since a very good argument can be made that Player A must have passed during his Upkeep if he's moving into the Draw Step.

Basically, A is correct, but should be careful, and B should learn the priority rules better so he won't get caught again.

[Anusien]

How do we know player A is in their mainphase?  How much time has elapsed?  It's maybe 1-2 word difference between the draw phase and the main phase.  Both players often pass priority there implicitly.  Now, I'm willing to believe Player B screwed up and didn't stop there, but if it was draw + land very quickly, Player B could have a case for being cut off before they could announce a draw step effect.

The best strategy?  At the end of your turn, announce stops.

[ELD]

I can see no reason why player B should not have acted during player A's upkeep, when player A attempts to go to his draw step.  To take it a step further it doesn't make sense as to why player B would not have cast Grip during his own turn, when player A was presumably ddin't have enough mana to activate slaver.  I love the split second mechanic, as it forces people to learn the rules.  There are a lot of very solid players who really are unclear on the specificcs of passing priority.  I don't think many Mind Slavers are going to fall victim to these split second cards.  If you don't have enough mana to activate Slaver after casting/welding, then the split second cards are just uncounterable boomerangs/naturalizes. 

I think Yawgmoth's Bargain is interesting, because if you draw a single card off it, you open yourself up to losing the enchantment.  You have to put a large number of activations on the stack, then pass priority, and at that point, you no longer have a boat load of cards to deal with whatever tricks your opponent may have.  A good example of this is a deck packing orim's chant, and split second removal.  As a Bargain player, what do you do?  Do you draw 1 at a time, and potentially only get to draw 1 total card?  Do you put 19 draws on the stack, and then have no counter in hand for orim's chant?  I still would rather be the player with Bargain on the table, then the player trying to stop Bargain, but it does give combo players one more thing to think about. 

[Harlequin]

I think the other situation in slaver will be when you have just enough mana to activate it. 

The other situation.. lets say that I play Slaver from hand (or tinker for it) with 4 mana open.  Now I put the mindslaver in play, and my opponent goes "KROSIAN GRIP !!one!11!2"  The real burden is going to be on the player with Grip to not just blurt it out w/o having priority.  Obviously, the player with Grip has screwed himself... because maybe the CS player was going to do sometihng else first... but probably not.  The grip player doesn't have much defense for his action so... but that doesn't mean judges won't/shouldn't be brought in to rule on the play.

[parallax]

The best option for the Grip player, when facing an opponent who is not declaring priority, is to wait for an implied pass of priority. For example, if player A plays a land without announcing the move from draw step to main phase, you can say "Wait, I have effects during your draw step." and play the Grip. Whenever player A plays a spell and looks at you to see if it will resolve, you can play Grip. If player A passes the turn, you can play Grip. If player A is sitting and thinking, he obviously has priority.

[Komatteru]

My gripe is this: Player B had ample opportunity to stop Player A at some point in this sequence.  When player A went to draw for the turn, B could have said, "Wait, on the end of your upkeep..."  If A had tried to argue that he wasn't finished, or hadn't passed priority, it would be apparent that such a claim is false.  By  going to draw a card, A implied that he was passing priority for his upkeep, and wished to proceed to the next step.  However, there's more still, as once A drew a card, B could have immediately said "inside your draw step..." or said "are you proceeding to your main phase?"  and then played the spell.  By asking such questions, it is possible that A might be able to deduce that B wished to play Krosan Grip, and then actives the Slaver while he has priority.  That really is a bit of a chink in the mechanic and rules of the game.  However, they do come with playing the game in real life, and wanting to play spells on another player's turn.  In a perfect MODO world, this wouldn't happen, but, then again, none of this would have happened on MODO in the first place.

I would rule that we went into A's mainphase.  B should have interrupted immediately and said he had an effect to play inside of A's draw step if that's what he wanted to do.

[Godder]

B had his best chance when A went to draw a card for the turn, although he could have done it during his own turn after Mindslaver was brought into play. Since he didn't take that chance, it's basically his own fault.

In general, if you have split second cards you want to play but you don't want to advertise the fact with questions about who has priority, wait until an implied pass comes up. Drawing a card for the turn is one possibility, as is someone trying to resolve a spell or ability (e.g. they play a spell and then ask if it resolves, or go to draw a card from Bargain as in ELD's example), and attacking also implies that the player has passed priority.

I don't think there's a chink in the rules, I just think that most players don't know the priority rules very well. This is nothing new, however, as the question "Can I cast Lightning Bolt?" is a well-known one from early days of tournament Magic.