I think our only concern should be to give some degree of fairness to people whose ISP disconnects them or when the chess.com server flakes out. This may well cause an outage way longer than the time limit of the game. An ISP outage of a half hour should not automatically cause someone to lose their 15 0 game.
Also, if the chess.com server goes down for, say, 3 hours, I suggest allowing maybe 6 hours to reconnect.
I think I agree with David Forthoffer - disconnects of less than - say 2 hours - should be allowed reconnect, resume. disconnect of 2 days, tough. loss.