[thejeff]

Originally Posted by Jarkko

That is the whole point, isn't it? The whole concept of strategical suprise is gone. Will you ever attack an opponent who is stronger than you if you have to tell him many turns before that you are going to attack? No you won't, it would be suicide. In a game with binding diplomacy, when you notice somebody is heading for victory the game is already over, there is nothing you can do.

That also neglects the other aspect of diplomacy: other people. Most of the time, if you notice someone heading for victory, you can round up other people to help attack him. Since you'll likely want to do this even in a non-binding diplomacy game and "I'm going to break my word to him, but you can trust me" isn't a very good argument, it may still be worth giving warning, so your allies will trust you.