we know we have some players who just care about victories and they would probably use that for helping their maina ccount with their secondary accounts....
What might be an idea was to be able to create some kind of official diplomacy in games, which would eb public and would allow players to ahve alliances.... without the possibility of back stabbing

Yeah, I suppose so, but then don't join an open game with that setting on unless you think it is a legit FFA. I already stopped joining open FFA's all together. I got burned once by that crap (without airlifts you can still just not attack each other and double team anyway).

Also, it should be a highlighted setting if turned on.

Just as with every other 'cheat', having this be a setting would make it a known situation for all players. It would be the player's fault for joining a game with that risk in place and would leave no room for legitimate complaints.