It's because they are post-trained to be agreeable, which is clearly a desirable trait in a model. I think the correct way around this is converting the conversation from first- and second-person direct, to third-person indirect, making the rope-playing obvious. I.e. '''prisoner says "I'm about to teleport to Narnia", what's the dungeonmaster's response?''', or even '''prisoner says he will teleport to Narnia [...]''' etc.