I remember the earlier seasons (ones before 7.0) sometimes cancelling matches if one team was down members for any reason, doesn't seem to trigger half as much anymore however; so the mechanic to end it does exist, but the trigger for starting the match seems to be higher priority in the current patch iteration.
Quote Originally Posted by Valence View Post
Also, I don't know if this is new, but I had a game yesterday where one player on the opposite team couldn't load (their portrait couldnt be loaded either, it was grey and showing "missing data"), and the game waited until the gates opened to actually cancel the game, so there is a system doing it, but I'm not completely sure under which circumstances... someone accepting the queue but somehow leaving before the instance can load them up? Sounds very unicorn.
That's been in since the start, only really seems to apply to players who DC mid-queue these days however, which given the long-winded way the game handles that given that their character is still technically logged in... yeah.