[Norfleet]

Well, that all depends on how you define "fair". Two players that know each other likely have an understanding of exactly how the other will behave, and will be less likely to provoke the other into premature and potentially undesirable violence. That alone can amount to implicit collusion. On the other hand, it's far from sound strategy to attack everyone you see like a slavering Zebranky: You're simply much more likely to try peace with somebody you already know, than somebody you have no experience with and probably distrust as a result.

So what defines "fairness"?