Originally posted by Joaquín Ossandón:

In the examples in the IPG you can actually find “A player activates a Sensei's Diving Top that is no longer on the battlefield, and sees 3 cards before the mistake is noticed”.

You're referencing an out-of-date copy of the IPG.

Edit: IPG as of April 16, 2016
http://wpn.wizards.com/sites/wpn/files/attachements/mtg_ipg_8apr16_ena.pdf

Edited Nathaniel Bass (May 11, 2016 12:54:54 PM)

Sorry, my judge core apps has SOI, but apparently not the corresponding IPG. My bad :)

Looking into the SDT example, Toby explains it's removal (this time, after-SOI :P ):

“This one was kind of a mess, as it’s in the crossroads between HCE (opponent can’t correct it), GRV (the activation) and LEC (the knowledge). Ultimately, it’s a misleading example. However, the way the rules are written and the expanded philosophy should place it more clearly into Looking at Extra Cards now, which is where it belongs. Fixing it doesn’t require opponent intervention.”

Considering the cards have been returned to the top of the library and one or more other actions has been taken since it occurred, I'm still behind ruling this as a GRV with no fix. The LEC policy states that once the cards have joined another set (being returned to the library in this case) that we no longer consider it as LEC and instead treat the infraction as HCE or GRV. Considering Toby's blog post, LEC would be correct if we haven't moved past the point of returning them to the top of the library and taking other actions, but in the case as posted, I believe we are in GRV territory.

Originally posted by IPG (LEC):

Once those cards have joined another set, the infraction is handled as a Hidden Card Error or Game Rule Violation.

A known number of cards being placed in a known position (the top three
cards of the library) is very different from the intended use of that
phrase, which is 3 cards being mixed with 4 others for a Collected Company,
or 3 cards being mixed with the hand. If you can resolve this as LEC
/before/ the three cards are placed on top of the library, then you can
resolve it as LEC /after/ that is performed too.

For GRV, quite a few people have said FtMGS for the opponent; is this true? Is this not a double GRV as the opponent, being the controller of Phyrexian Revoker, has a reasonable level of responsibility here?

Originally posted by Dan Collins:

A known number of cards being placed in a known position (the top three
cards of the library) is very different from the intended use of that
phrase, which is 3 cards being mixed with 4 others for a Collected Company,
or 3 cards being mixed with the hand. If you can resolve this as LEC
/before/ the three cards are placed on top of the library, then you can
resolve it as LEC /after/ that is performed too.

LEC seems fine if you catch the error immediately. If actions have since been taken based on that information, or cards have been drawn or further manipulated in some what way, then what? If the error is not caught immediately, you're going to reach a point where the LEC fix would be overly disruptive or impossible to apply. Considering the player here has played a fetch land and then cracked it since the error occurred, based on knowing what those cards are, I feel we've approached the point where the LEC fix is no longer appropriate.

Edit: Also, the LEC example cited by Toby is looking at 3 cards from a top that doesn't exist in play anymore. In this example we have a top in play, but it cannot be activated due to the Revoker/Needle. To me, this scenario seems more like a GRV than just randomly looking at 3 cards with no top in play.

Edited Nathaniel Bass (May 11, 2016 05:35:12 PM)

Originally posted by Sophie Hughes:

For GRV, quite a few people have said FtMGS for the opponent; is this true? Is this not a double GRV as the opponent, being the controller of Phyrexian Revoker, has a reasonable level of responsibility here?

The example in the Annotated IPG feels a lot like the one in this case and that seems to indicate FtMGS.

As always, both players are responsible for maintaining a clear game state. If my card tells you to take an action, and you do it incorrectly, whose fault is it? Yours for doing the action incorrectly, or mine for not making sure my spell resolved correctly? Turns out, in this case, it’s reasonable to say we are both equally at fault. It’s important to realize this is only for active effects. If player A forgets to pay 1 more when casting a shock because he forgot about player N’s Thalia, Guardian of Thraben, that is not considered an active effect on player N’s part. In that case, the error is on player A’s shoulders, and player N should get a Failure to Maintain Game State.

Phyrexian Revoker and Thalia appear to be very similar.

Edited Quinten van de Vrie (May 11, 2016 02:31:46 PM)