Small suggestion.

[Sharples]

If you have a DoF with Civilization and you trade them most/all of their gold for what you offer and then you declare war on them, maybe we can stop this exploit by punishing the player with giving them aggressive expansion penalties. Sure it doesn't make sense to have aggressive expansion penalties for gold, but it'd tell the others AIs to not trust the player even more! If an AI gives you all of their gold this should warn other AIs to either give you a agressive expansion penalty, or to punish the player by not letting the AIs trade GPT/Gold with the player.

I think it's reasonable to stop DoW for Gold exploit.