This has already been adressed in http://brainking.com/en/ReadBug?bgi=1164&utf=GO and I agree that it's not a bug - but it's still an unresolved Problem. (In Go 13x13 (heyo vs. goldhaus) my opponent wants to prove that he just can't loose)
My suggestion to handle this: after the game has ended and players don't agree about dead stones both are forced to place at least one stone befor they may pass again. A player who can't legaly place a stone looses the game.
This may lead to a new problem if the game's ending is slightly in favor for white (only by komi), but would solve the problem that by the rules as they are now nobody can ever win a game of GO if the opponent doesn't agree.