[DragonRider]

Personally, my understanding is that if the message breaking the pact arrives at turn 16, it is appropriate to give invasion orders on turn 18 so the battle happens at 19. The idea is to give the person three turns to prepare before the war starts. Under that interpretation, if the defender has troops three turns away from the border, they can be there to reinforce it before the first battle happens (since movement into friendly territory always resolves before movement into enemy territory). That tells me that the terms were honored.