Aria casts a Thundermaw Hellkite and attacks with it. Then she notices she didn't have double red. Rather than call a judge, she just takes the Hellkite back in hand, untaps her land and mentions that she's already past her attack phase now because of that mistake.

What is Noir required/allowed to do in this situation? Can he stay silent about it and continue playing?

Edited Toby Hazes (Sept. 19, 2013 01:46:54 PM)

What can she, or should she do? - Call for a judge.

We as judges want to encourage players to not fix these things themselves, and let us help them out, and make sure there are no other things that need attention in the game. Reality is that players do this often, and we rarely hear about it (ex: Path to Exile, creature in graveyard, player notices, and puts it in exile). If I was called over to the table, I would fix it correctly (back up or not), then educate the players on calling a judge for these situations.

There has been much concern for what is the opponents obligations are during a match. Too much IMO.

Unless Noir wants to interject something he is not obligated to stop Aria from skipping combat. It might be considered shady to let her do that. Not our area to judge.

Is this how we want players interacting? No. That is not how you properly fix the situation. I feel it's bad customer service to let it happen if we see it.

If a judge sees this happen I would recommend the following:
With permission of the HJ to downgrade (she caught the error) and rewind. I would issue the penalty GRV downgrade to caution and rewind to Aria's main phase 1. Remind Aria to next time call a judge, fixing it yourself can penalize you further than you're supposed to.

As Michael said we want players to play magic and not worry about the little details of “gotcha” for penalties.