MadMonkey: Your opponenet would not get a chance to pass. They would have 1 more move, then after that the game would be over since they would no longer be able to play, and at that point - the player with the most pieces (you) will win.
I agree with the rule, it makes the game interesting - kind of like chess - you can be killing the person and have 10 pieces left, while the other player just has their king left - but if you mess up and not place them in check and they have no legal move, it is a stalemate (draw) since they are unable to move - even though you should win, just one of those rules you have to be carefull on... just like here - if you are going to block your opponent in, make sure you have more pieces then they do.