In my last game as of writing this, my opponent became unresponsive in the middle of game 2, and I had to wait for an effect to resolve for 8 minutes. In that wait time, I did call a judge. When the opponent came back, I continued with the match to not cause a "pausing play" infraction.
The match ended in my favor before a judge showed up, and I do not believe the AFK was malicious, so the highest penalty I would reasonably anticipate is the opponent being given a game/match loss.
However, I would like to know for the future: What is the correct to handle this if the opponent AFKs for 6+ minutes, which the rules imply should result in a game/match loss, and the game/match ends in the offending player's favor before a judge shows up? Do I "report abuse" the game in question here? What would be expected of me in that scenario?
