AP has to perform action 1 followed by action 2, but uses Out-of-Order-Sequencing to perform action 2 followed by action 1 instead. One of the actions is performed incorrectly. When backing up, do we treat the game state as though the actions occurred in the order they were physically performed, or do we ignore the OoOS and pretend the actions occurred in the technically-correct order?

For example: AP casts a Soul Warden, plays a land, then writes down a gain of 1 life. When asked, they say they thought that Soul Warden triggered on itself entering. Do we back up only the incorrect lifegain, or do back up to before the land was played, when the trigger should have resolved?

Edited Isaac King (Aug. 23, 2018 11:01:24 AM)

Closed awaiting an Official answer.

I've been reminded that this is still outstanding. When I seek insight from others on situations such as this, I often forget that I asked and am waiting for a response - and then these things just kind of fade into the background. Apologies, Isaac!

In your specific example, I think we just correct the player's misunderstanding, and their life total, and move along:
“Nope, it doesn't work like that - see where it says ‘another creature’? OK, fix your life total.”

I also had a hard time finding any examples that (a) would actually happen and (b) would actually matter. I don't mean to belittle the question - in fact, the general concept in question is an interesting one - but actual occurrences make it much easier to arrive at a guiding principle for us to follow.

The philosophy that allows us to consider Out-of-Order-Sequencing is, in short, if the end result is OK, and nothing was wrong along the way, then we don't care if the order wasn't technically correct.

Your question is, essentially, “what if something actually is wrong along the way?” - and I suspect that the best solution is to simply back up everything, to the point of the first chronological error. By “chronological” I'm saying the step in the sequence as it should have been sequenced, not as it actually was sequenced.

Again, I can't think of real-world examples that matter, so I'll be more generic:
I'm going to perform A-B-C-D-E, but I actually do A-C-E-B-D, and I commit a GRV during step B. We could easily just back up D and then B, but it's probably safer, as a general guiding principle, to back up D, B, E, and then C, since C and E should have come after B, and thus maybe can't or won't happen after we fix B.

Of course, when this actually occurs, I think using your best judgment will override that general guidance; it may be perfectly safe and sane to simply back up D and B in that example, let them fix B, and then maybe continue with D. Or it may be clear that C and D can't happen, and I no longer want E to happen if that's true, so…

d:^D

Maybe I do not get your point…
But I could imagine something like:

I am at 1 and my opponent has Eidolon of the Great Revels.
Thus I want to activate my Scavenging Ooze three times (A), write down +3 life (B), cast Fatal Push (C) and get 2 damage (D). Since I am a lazy person, I just tap 3 green mana, write down 2 (As it will be my resulting life total) and throw fatal push onto the table (So I did A-(B+D)-C). Maybe I even told my opponent that I will go for fatal push and they tracked the life total the same way as I did.

My opponent calls for a judge and notices that I tapped a mountain for my push.

Obviously, I will go to 4 life instead of 2, right? So we should not just backup action C, which was the last one performed. I am not sure though, if that scenario fits into your discussion…

I would back up the illegal action - casting Fatal Push for R instead of B - which also means that the Eidolon never triggered. There's nothing illegal about the three Ooze activations, so your life total after reversing the Eidolon trigger that didn't happen is, indeed, 4.

d:^D