Originally posted by Jason Flatford:
What infraction would you say the player committed here?
Well, I think there's two points here.
The first is that there is a policy that makes clear the player can't advance the game state in order to cause the opponent's triggers to be missed. It's part of the Missed Trigger policy, and makes clear that in order for the trigger to be missed, the controller of the trigger has to actually miss the trigger. I feel that runs contrary to your earlier point: The policy is pretty specific that the player can't cause the opponent's trigger to be missed.
The second is whether or not an infraction has taken place. Clearly if this is accidental, especially if the player isn't aware of the trigger, there is no infraction. Nothing in policy states the player accidentally missing the opponent's trigger has committed any kind of infraction; quite the opposite, as the player has no responsibility there. But, if the player is aware of the trigger, is knowledgeable about the policy, and deliberately and with intent tries to cause the trigger to be missed… I don't see how the infraction can be anything other than UC–Cheating.
Perhaps I am mistaken, or you feel otherwise, but I certainly see a pretty serious issue here that merits further investigation. If the opponent is trying to angle shoot that significantly, then at a minimum, he or she is due for some serious education.