NAPs and Treaties
Personally, I believe there should be no guidelines for truces. A persons word is his bond, I had success in Battleforces by knowing who to trust, others who were sketchy, and new players who I kept my eye on. Made for more fun in my honest opinion. I enjoyed being dependable, therefore reputation ensured I had some early advantageous truces over other lesser known players. As we know from history there are nations, e.g. Hitler, who broke truces and it should be the same here.
The purpose of having guidelines or "rules" for truces are exactly to establish an accepted framework that is fair and reasonable to the parties that both can trust. Of course players can (and will) negotiate whatever terms they see fit in the end, and LOL regardless of how many guidelines or rules are established there will ALWAYS be players who break their truces/violate the terms. That's never going to change. My point is it's pretty clear that all the reasons you state for believing there should be no guidelines will be a part of the game regardless.
Sad the admins never responded to this. I was just looking for the classic WWII version in the heads up format as well but what they have now is just that map divided into 2 players, instead of the 5 nations classic where one controls Axis and one Allies. I hope if the site is ever rekindled, this becomes available again.