Putting up the Forge, to me, typically is the "i win" statement. When you put it up you basically are telling the World beat me if you can-i do not think you can.
I consider NAPs terminated with the nation casting the Forge. In other words, if I have a nap with you, and you want our nap to continue, I expect you to get my blessing(in advance) to cast the Forge. Otherwise you may see my armies on your doorstep.
And typically my blessing for a Forge casting does not come cheap.
