I am building a whole deck around this interaction, so I'm looking for rules references and/or a judge's ruling.
Example #1: I play Skill Borrower, reveal Snarling Wolf, use its ability, play Sage Owl, look at the top cards of my deck, and return them in the same order. Can I use the Wolf's ability again?
The trick here is that opponents usually can't know whether I have two Wolves in the top four cards of my deck. I suspect this means the Wolf become a new object?
Note: See my analysis of the comprehensive rules in comment #5 below.
Example #2: Conspicuous Snoop + Akki Avalanchers (or similar Adapted creature) + any multi-card scry/rearrange effect. Can I use the Avalanchers' ability again?
Those are my "real-world" examples, but I really want to extrapolate the rules to Yet Another Aether Vortex and Faerie Seer (on top of my deck), to determine whether I could infinitely scry through my deck.
Thank you!
Also, if my opponent Extracted a card from my deck, they might know for a fact that I only have one Wolf in my deck. That wouldn't change anything, would it?
701.16c If cards in a player’s library are shuffled or otherwise reordered, any revealed cards that are
reordered stop being revealed and become new objects.
401.6. If an effect causes a player to play with the top card of their library revealed, and that particular
card stops being revealed for any length of time before being revealed again, it becomes a new
object.
One could argue, that a revealed card, that is put into the same position as before is not being reordered, but as you said, that causes issues with potential multiples, that cannot be verified. So 701.16c has to mean, that the card becomes a new object and you can use the copied ability, since it is a new instance, that hasn't been used yet. (And no, any information gleaned by other players or even yourself prior to the reordering has no bearing on this, nor does a format, where only one copy is allowed.)
As for the silverbordered scenario, since the Faerie becomes a new object and thus goes from not being on the battlefield to being on the battlefield (= entering the battlefield), you get to scy 2 for every scry 2 you do. You will have to stop that loop eventually, though, by scying the Faerie away from the top. It's silverborder land, however, so there are no hard rules for dealing with that nonsense. You could ask the Un-rules manager Mark Rosewater, if you want a more "official" answer.
Here's another real-world example that demonstrates the same issue: Temporal Aperture + any multi-card scry or rearrange effect, returning the same card to the top of your deck. This poses the same question as before - either the returned card is the same object (put face up and may still be played for free) or a new object (put face down and cannot be played anymore).
Edit:
Here's another rules reference: 401.4. If an effect puts two or more cards in a specific position in a library at the same time, the owner of those cards may arrange them in any order. That library's owner doesn't reveal the order in which the cards go into the library.
It seems I'm not the only person asking questions about this stuff:
It appears that your underlying question is thus: If—
a player plays with the top card of their library revealed, and
that player looks as the top two or more cards of their library and puts them back in the same order (or while keeping the top card in the same order as before),
is the top card of that library "reordered" for purposes of C.R. 701.16c, and if not, does that card "sto[p] being revealed" for purposes of C.R. 401.6? (But under C.R. 701.16d, looking at a card generally "follows the same rules as revealing a card".)
@peteroupc Yes to your bullet points. The problems as I see them are:
1) "Reorder" isn't defined by the comprehensive rules, so it isn't clear whether cards that are returned to the same position count as having been reordered.
2) In 701.16c, in the phrase "any revealed cards that are reordered...," it isn't clear whether the rule is referring to cards that are "actually" reordered or, more broadly, cards that are included in a reorder effect (even if they were returned to the same position).
3) 701.16 ("...If an effect causes a card to be revealed, it remains revealed for as long as necessary...") conflicts with 401.4 ("...That library's owner doesn't reveal the order in which the cards go into the library") So, it isn't clear whether you continue to play with the card revealed while you are reordering (it's still on the top of your deck after all) - and it only stops being revealed if you would move it to another position. And if you do move it to another position, could you move it back? (undoing the move but still keeping it hidden)
4) Bonus question: As I understand it, you can shuffle a 1-card library. Can you reorder a 1-card library? Would doing so cause that card to become a new object?
You should ask your questions to the rules manager, Jess Dunks (dunkatog on Twitter); your questions arguably have no clear answer under the comprehensive rules.
Example #1: I play Skill Borrower, reveal Snarling Wolf, use its ability, play Sage Owl, look at the top cards of my deck, and return them in the same order. Can I use the Wolf's ability again?
The trick here is that opponents usually can't know whether I have two Wolves in the top four cards of my deck. I suspect this means the Wolf become a new object?
Note: See my analysis of the comprehensive rules in comment #5 below.
Example #2: Conspicuous Snoop + Akki Avalanchers (or similar Adapted creature) + any multi-card scry/rearrange effect. Can I use the Avalanchers' ability again?
Those are my "real-world" examples, but I really want to extrapolate the rules to Yet Another Aether Vortex and Faerie Seer (on top of my deck), to determine whether I could infinitely scry through my deck.
Thank you!
Also, if my opponent Extracted a card from my deck, they might know for a fact that I only have one Wolf in my deck. That wouldn't change anything, would it?
Links:
79 Other creatures with "once each turn" abilities: https://scryfall.com/search?q=type:creature oracle:\: oracle:activate oracle:"each turn"&as=grid&order=cmc
118 Other multi-card scry effects:
https://scryfall.com/search?q=oracle:"scry 2" OR oracle:"scry 3" OR oracle:"scry 4" OR oracle:"scry X"&as=grid&order=name
38 Other rearrange effects: https://scryfall.com/search?q=oracle:"back" oracle:"in any order"&as=grid&order=name
One could argue, that a revealed card, that is put into the same position as before is not being reordered, but as you said, that causes issues with potential multiples, that cannot be verified. So 701.16c has to mean, that the card becomes a new object and you can use the copied ability, since it is a new instance, that hasn't been used yet. (And no, any information gleaned by other players or even yourself prior to the reordering has no bearing on this, nor does a format, where only one copy is allowed.)
As for the silverbordered scenario, since the Faerie becomes a new object and thus goes from not being on the battlefield to being on the battlefield (= entering the battlefield), you get to scy 2 for every scry 2 you do. You will have to stop that loop eventually, though, by scying the Faerie away from the top. It's silverborder land, however, so there are no hard rules for dealing with that nonsense. You could ask the Un-rules manager Mark Rosewater, if you want a more "official" answer.
Former Rules Advisor
"Everything's better with pirates." - Lodge
(The Gamers: Dorkness Rising)
"Any sufficiently analyzed magic is indistinguishable from science."
(Girl Genius - Fairy Tale Theater Break - Cinderella, end of volume 8)
Here's another real-world example that demonstrates the same issue: Temporal Aperture + any multi-card scry or rearrange effect, returning the same card to the top of your deck. This poses the same question as before - either the returned card is the same object (put face up and may still be played for free) or a new object (put face down and cannot be played anymore).
Edit:
Here's another rules reference: 401.4. If an effect puts two or more cards in a specific position in a library at the same time, the owner of those cards may arrange them in any order. That library's owner doesn't reveal the order in which the cards go into the library.
It seems I'm not the only person asking questions about this stuff:
is the top card of that library "reordered" for purposes of C.R. 701.16c, and if not, does that card "sto[p] being revealed" for purposes of C.R. 401.6? (But under C.R. 701.16d, looking at a card generally "follows the same rules as revealing a card".)
1) "Reorder" isn't defined by the comprehensive rules, so it isn't clear whether cards that are returned to the same position count as having been reordered.
2) In 701.16c, in the phrase "any revealed cards that are reordered...," it isn't clear whether the rule is referring to cards that are "actually" reordered or, more broadly, cards that are included in a reorder effect (even if they were returned to the same position).
3) 701.16 ("...If an effect causes a card to be revealed, it remains revealed for as long as necessary...") conflicts with 401.4 ("...That library's owner doesn't reveal the order in which the cards go into the library") So, it isn't clear whether you continue to play with the card revealed while you are reordering (it's still on the top of your deck after all) - and it only stops being revealed if you would move it to another position. And if you do move it to another position, could you move it back? (undoing the move but still keeping it hidden)
4) Bonus question: As I understand it, you can shuffle a 1-card library. Can you reorder a 1-card library? Would doing so cause that card to become a new object?
Also, I noticed the problem is not limited to "once each turn" effects. The same questions arise with linked activated abilities, like the ones on Muse Vessel. https://yawgatog.com/resources/magic-rules/#R607
Same goes for Nth Activation effects: https://scryfall.com/search?q=oracle:time oracle:"this ability"&unique=cards&as=grid&order=name