Adjourning would really only matter if you can reliably reschedule the game with that player, which means open communication. In most situations, I imagine that if they are not back within, say 10 minutes or so, you will never get to finish that game. Abandoning without recording a win/lose is certainly an option.
I'm not against the idea of suspending a game (which I think is a better term than adjourning), I think it can be useful when friends play each other, I just see it as having very limited applications, and doesn't really solve the problem you are describing.
I'm not against the idea of suspending a game (which I think is a better term than adjourning), I think it can be useful when friends play each other, I just see it as having very limited applications, and doesn't really solve the problem you are describing.