I noticed since BNW came out, that either the AI is trying to trick me, or there is some bug here. As long as the AI is willing to negotiate about peace with me, they will agree to white peace, even if they are massivily more powerful than I am. If I click the "What deal will end this conflict?" button, they will ask for all my cities, but I can just click those away and the deal will work fine. Since it could be that the AI is just trying some bluff by asking for all my cities, I thought I'd ask people to keep an eye on this, and try suggesting a white peace in their next games if you are in a situation like this, to see if it's a bug. Here's a save where you can see what I mean, go ask Napoleon what deal will end the conflict, and you can see him wanting 5 of my cities, then just remove those cities from the trade window and he'll agree to the white peace anyway. It's using the beta patch, though the bug/feature/oddity has been present since BNW launched.