For doing dailies like playing 45 lands or attacking 45 times, especially the later. People just ended the game while I was trying to create as many creatures as possible, let alone I was about to attack. I just dropped the creature and they quit.
I suggest when they hit the Concede button burn all their timers, auto pass all, so I can do my things. Treat it like a disconnection but they will skip that match if "trying to join back". Like Sparkie