I have seen some strong players with prearranged teams. One of them is in the top 10 right now, so I do think it is quite an important issue. If I understood chat correctly they should have been reported.
What to do with cheaters?

I guess my point was while they are working out the details of how to stop cheaters we can self police a little bit by recognizing if two people are teaming up (actively cheating -*same room, pre-arraigned, same person) and if chat is still open reach out to the 4th person create a quick team and go after them in response. If not then go after them anyway help the odd man out and hope he helps you. It's not much, its not perfect but I for one don't plan on lying down and rolling over when it happens in a game I'm in. Win or lose I'm going to change my focus on the game and go after the cheaters even if it hands the game to the other person (non cheater).

i dont think its really cheating since some people like to have a friend on their side. My friend, DJOagent, we friended since we teamed on 4 player chess
And do you declare up front during the first 4 moves that you are playing as a team so that you give them a chance to abort? Or do you just play it out without saying anything? Because I think that's the point, is that in 4-player it's meant to be every-man-for-himself with an element of temporary alliance, not 2-on-1-on-1. Teaming against people without telling them is really lame

And do you declare up front during the first 4 moves that you are playing as a team so that you give them a chance to abort? Or do you just play it out without saying anything? Because I think that's the point, is that in 4-player it's meant to be every-man-for-himself with an element of temporary alliance, not 2-on-1-on-1. Teaming against people without telling them is really lame
Well said.

@PWChessPlayer thanks. Corrected. :-)
My opinion on the subject is that players who are known to form prearranged teams should not be allowed to play together in the same (FFA) game. There should be a list of "toxic" pairs in the server database, and the randomized matching procedure should ensure that these are always separated.
uhm I have seen lot of games and my impression is that Bobby is right
have experienced myself the issue but often these cheaters are not strong players and can be easily tricked