I was curious about what would happen if this sernario was to occur since it is not secret diplomacy and is not covered by rule 2, yet it is clearly "cheating"....
What if two people were to enter in a standard game. In the first few rounds, one of the players proposes an alliance (in the game chat) where both work together to eliminate every other player then at that point fight each other. The other person accepts and both kill off all the others because they are working together as "team mates," then one of the two wins the game and earns a lot of points. This process may then be repeated in another game where the other person becomes victor, thereby both gaining points.
This seems like it is crossing some sort of line to me, but I could not find anywhere on the rules page where it said that this sort of this is not allowed.
Is this kind of tactic really possible or is it an unwritten rule that you can still be banned for?
[note: I have not seen this sort of thing occur or taken part in it myself. It is an idea I came up with but wanted to see if it is "legal"]