Re:Nasty Sidestep Retreat
I have the same question.
Let's simplify it a bit though first.
Dark player attacks light player. Assume that the battle makes it to the card playing and that each player only has one card left. The dark player has a retreat card. It doesn't matter what the light player has for this question. Assume that the dark player would win the battle if he didn't retreat. Must the dark player obey the text on the retreat card, thus running away from a battle that he would have won, or may he choose to ignore it?
My wife (the light player) determined that if the dark player were allowed to ignore the card's text then the dark player would be able to use the retreat card as a way of "scouting" the light player's card and then if the dark player determines that he can win if he ignores his played card then he'll just ignore it. Otherwise the dark player would just retreat. This really would seem unfair.
We decided that a card played is a card played and the dark player in this case MUST retreat. We figured that Pippin (the light character in our example) had tricked the Balrog (again, in our example) into thinking that he (Pippin) was a big and nasty creature so the 'Rog decided to turn tail. The lesson learned was to not get stuck with a retreat card when you must play it and you don't want to retreat (unless you can't retreat, etc).