Idea for a game (not gamemode), wanted to see what you all thought

WW3, 4X speed. Server wide agreement to not attack another player before day 60, for example (just a really late day in the game). Attacking AI nations before this is ok. Coalitions can be formed. A warning will be given by someone 1 day before the fighting starts.

Watch the chaos unfold when the fighting begins.

What do you think?