Revision of spell timing at the Pro Tour
There was an interesting judge call during round 13 of the Pro Tour that was captured on coverage. It's possible that there are details of the call that were not apparent to people watching coverage, so my apologies if there are relevant aspects of the call that I'm not privy to.
The active player draws for his turn and casts a Hellraiser Goblin. It appears as if the Hellraiser Goblin resolves, and the active player at this point calls a judge and asks if, even though he didn't announce that it was his second main phase, whether he can decide that he has cast the Hellraiser Goblin in the second main phase. The judge appeared to have approved this request.
This seems like an incorrect ruling to me, but I think it's worth discussing. I think this call can be handled in one of two different ways. First, we can, after asking both players about the game state, decide that there was no communication about moving to second main phase and rule that the Hellraiser Goblin was cast in the first main phase, particularly since the players so far have been casting spells both pre and post combat and the distinction between the two has been based on actually attacking in combat. Alternatively we can decide that there is unclear communication between the players about what phase we were in, and therefore choose to rewind the game state to the last point where they were in agreement about the game state (i.e. before the Hellraiser Goblin is cast, with the stack empty in the first main phase). How should this call be handled?