Like we really need another topic on this, but I think it is important to really try and identify what collusion looks like.
Let me start by saying that I believe the Missouri meta colluded in 2009. I remember driving to Gencon that year and having the discussion how we would always work together when playing at the same table. There were no collusion rules at that time, but clearly we colluded.
FFGs current tournament rules specifically states that premeditated collusion is prohibited.
In my mind, collusion is any premeditated decision made outside of the actual game played at a table that helps someone else and manifests itself through actual game play.
So if hypothetically, Kennon and I realize we've found an infinite win Dual-deck combo by each of us playing King's Landing Joffrey and putting Apprentice Collar's and Gold Link's on our Joffrey's, and then hoping we end up at the same table so we can pull off the combo, we have made a premeditated choice to help ourselves and help each other by playing the same combo/deck. Now, if we never end up at the same table, our premeditated decision will not manifest itself in the form of "in -game" assistance thus it will be collusion that never can be proved, and collusion that never helped us or hurt our opponents.
The idea of a melee tournament is that you are ONE of many trying to win the championship, not TWO of many, or FIVE of many, or FOURTEEN of many. When you make a decision about YOUR deck that intentionally helps another before the event starts, or another person makes a decision about their deck that intentionally helps you, you are no longer ONE of many trying to win.
So when looking at what happened at the World Championships, ask yourself this simple question, did that group of 14 players make a premeditated choice to bring a deck that they knew grew exponentially better when playing at a table with a friendly metamate using the same deck? Yes they did. Not only did several of them admit it at the event, but it was obviously manifested in many games throughout the tournament. Did they also believe it was the best deck available? Yes they did, but that isn't the point. An intentional, premeditated decision was made to play a deck that grew in power when played at a table with a deck using the same combo.
Now, all that being said, anyone who has ever said to a friend "we will work together if at a table together" has essentially colluded in melee. They just may not have a brilliant deck design to back up it with