I've been inundated with messages today and yesterday about an incident that happened on Saturday's PPTQ at Border City games.  So here's some explanation of what happened and my thought process during the event.  This post is purely my own and is independent of Border City Games, so I hope nobody throws any undue criticism at the store (who I am pleased to say were a pleasure to work with).

What happened:
Active Player cast Claustrophobia enchanting a creature. Active player does not make any mention of the enter the battlefield trigger. The creature remains untapped, with claustrophobia covering a good chunk of the card. Several turns later, Active player attacks and Non-Active player attempts to block with the untapped, but still Claustrophobia'ed creature.  Active player says that the card should be tapped and therefore unable to block.  This is the point when I am called over.

For anyone who hasn't been paying attention to the rules updates in the past year, there has been a slight change that affects exactly this situation.

From the Magic Infraction Procedure guide, Section 2.1 Gameplay Error - Missed Trigger

"Three types of triggered abilities do not expire and resolve immediately if they are discovered:
...
- An enters-the-battlefield trigger of an Aura that affects only the enchanted permanent and causes a visible change to that permanent."

This is the appropriate policy for this situation, as it meets all of the criteria.  Claustrophobia is an aura, it has an ETB trigger, and it affects only the enchanted permanent by means of a visible change (i.e. tapping it).  This is different from a normal, beneficial missed trigger where an opponent will be offered the choice if they want to put the trigger on the stack.

Now, this is relatively new policy, and while I had mentioned it in passing to a couple of players during the event, I had made no such direct announcement to either player in this incident.  In retrospect, it would have been prudent to do so, and perhaps on my part to do more research on the set and rulings.  (I did announce the new Magus of the Moon interaction, but not this one, as this policy is slightly older).

So, I gave my ruling to the players, and the Non-Active player, who stood to lose game advantage from my ruling (as he had been playing the game assuming he had a blocker his opponent didn't know about).  Now, Non-Active player became upset, and challenged my ruling. As I am the Head Judge with no other judges on staff, my ruling is and will always be final. For rulings like this, I like to provide the upset party with the quote from policy that supports my ruling.  It takes me quite some time to find this ruling, as I know the ruling is in policy, but I'm unsure in which section of which document the policy in question is in, and what phrasing I should be searching for.  Eventually I find an article from the magic judges blog (https://blogs.magicjudges.org/playerexperience/2017/10/17/triggers-in-competitive-events/) that quotes the rules section, but in my haste to find the ruling, I bypass the section of the article/rules that clearly says "do not expire and resolve immediately", and instead am reading the line that says "Claustrophobia is the best example here — when it enters, it is supposed to tap the enchanted creature. If Arthur casts it on Nicole’s creature but doesn’t acknowledge the trigger when it enters the battlefield, before moving on with his turn, the trigger will happen when he notices it.".  Active player saw this and debated the meaning of the English used, and said that it didn't support the tapping of his creature three turns later.

I returned to the table and said that my ruling is final.  Active player became visibly upset, and accused his opponent of cheating.  I informed the player that accusing your opponent of cheating is not allowed and if he continues he will be penalized with unsporting conduct.

I investigated the cheating accusation, and based on my observations of the player during the Swiss and Top 8, was fairly certain that the player was not cheating.  I've had discussions with several judges in the community about the finer points of the investigation, I believe there are some more questions I could have asked in my investigation, but those particulars aren't really relevant to those outside of the judge community.

To clarify for anyone wondering - In these scenarios, we would issue a USC-Cheating penalty along with a DQ:

-Player knows that Claustrophobia will always tap the creature, but neglects to demonstrate it until an advantageous combat.
-Player knows that their creature will be tapped by Claustrophobia when it's pointed out, but hopes the opponent doesn't know the policy and will let him block

The following scenarios will result in a DQ
-A player does not know the change to policy and does basically anything that would be acceptable under previous rules
-A player does know policy, but lies to a judge about their knowldege and uses it to their advantage.

Furthermore, if players are concerned about the conduct of a player during the event, they are HIGHLY encouraged to bring it to the attention of a judge or TO.  Even if something seems small early, we have fantastic policy for dealing with repeat offenders. However, if we only find out about incidents well after the fact, there is much less we can do, especially after the event.

If you have strong feelings about the policy or judging, you are welcome to fill out the Judge Feedback Form, available here: https://blogs.magicjudges.org/conduct/feedback-form-2/

Or you can contact Jon Goud, the Regional Judge Coordiator for Canada if you have questions about anything where a judge was involved: https://blogs.magicjudges.org/contact/contact-a-regional-coordinator/