To Arctijedi: I agree it is a procedural error and should be handled as such. Even those could escalate, right? Once the two have been played straight to the discard and there is no unwind... ouch.
To all discussing, here is what I see as the problem with the issued raised, specifically, and focusing on results of game actions (knock out, etc.) to the exclusion of game play rules in general.
Looking at it from the perspective of the opponent, the game rule is partly for them, a courtesy, a placeholder, even communication. A LOT of stuff can happen in a turn as combos begin to fire. Using the game state markers designed into the game is also for the opponent, not just the player or the judge.
Habitually omitting to play with game state markers (counters, card orientation, calling your attack) is not a good thing and makes the game hard to follow, ESPECIALLY for newbies. We want more players in the game, not people who are like 'Pokemon, whatever' because we made their heads spin. This might not be the case in your league but playing the support straight to the discard is usually accompanied by omitting all other game marker, not calling any attacks or powers. In short, watch carefully and figure out what I'm doing.
One person plays that way because they're all casual and focused on their moves and strategies rather than the game, and another sees it as an opportunity for advantage. There are elements of both reasons for the procedural errors that are problematic. With prizes (big or small) on the line, with just simply winning or a players sense of fairness on the line, the judge has to teach people how to play right.
