Saw the following at a regular REL draft the other night; players fixed it, but I was wondering how it would be handled at Competitive:

Albus attacks Nymphadora with a Meandering Towershell and exiles it. He passed, Nymphadora takes her turn, and passes back. Albus says, “Attack you with all my morphs on the board. In the declare attackers step, trigger Meandering Towershell. Wait..where did it go?” Nymphadora looks under the table. Neither player can find it; then, Albus checks his face-down cards. “Whoops!” he says, turning one of them face up to reveal the Towershell. Nymphadora calls a judge.

Clearly this is a GRV. However, most morph cases are upgraded to Game Loss given the hidden information. Since both players know the Towershell exists and where it's supposed to be, would Albus get off with a warning?

No Game Loss here.

The GL for Morph is actually an upgrade from the normal Warning for a Game Rule Violation (GRV), appropriate when “an opponent cant verify the legality” of the error. It's not “the Morph rule”, but Morph is a topical and timely example.

d:^D

Do we partial fix and flip the Towershell?

There is nothing here to partial fix. The players just made a bad choice about the way they wanted to represent Towershell being exiled. Make the representation of the game state match the actual game state and move on.