[Belac]

I really don't think it makes that much of a difference. A well-timed announcement that a NAP-3 will be retired can be as devastating as a full-on sneak attack, especially if you've been talking all friendly-like, discussing alliance possibilities, and the other guy was -absolutely- convinced he could declare war on another of his neighbors.

In other words, binding diplomacy does not mean no deceit and scrupulous honesty. It means you have to be just a little bit more subtle if you want to catch someone out.

(Also, I will very rarely make a formal agreement to not fight until 'x' turn, or to not make peace with 'x' nation, etc. 'I will not do 'y' unless I give you 'x' turns warning' is very different from either of those)