The notion that a player may tell all the lies he wants and cross people as he pleases etc., make some people almost euphoric and causes others to “shake like a leaf”, as one new player put it, came up almost incidentally, because it was the most realistic in international affairs and also far and away the most workable approach. To require players to adhere to alliances would result in a chivvying kind of negotiation followed by the incorporation of contract law – as some erstwhile variant: inventors have discovered.
I wouldn’t call myself an avid player of Diplomacy in any sense; just don’t have the time. Nevertheless, when I do play– often with a group of new students– I find it endlessly fascinating to see which become euphoric and which shake like a leaf. I doubt it will surprise anyone to find that bitterness over particularly brutal Diplomacy betrayals seeps into academic and even professional relationships. In any case, RIP.