The Enemy Within: Pride
One of the often unnoticed differences between PBeM and FtF gaming is the different senses and recognitions of authority. While a gamemaster may have ultimate authority in many places within the game, there remain positions where one character or one player alone may have the final decision.
For example, one common element of authority is "camera time." Whether this is a guaranteed fair-measure, or a "catch the GM's attention as one can," the person who the GM is giving attention to has authority. A loud voice or a pre-prepared action may be able to offer input, but there are concerns when interfering with that time.
Other elements may include character background, wherein a GM may suggest situations or events that occurred, but it is the authority of the player who created the character to determine whether things happened that way. There's consensus authority, wherein "we like this to have happened this way," can decide the fate of a conflict. There might be a natural leader, a character or player with charisma to which the rest of the group tends to allow to make decisions.
Groups without an authoritative structure may have characters with non-competitive goals or who otherwise have learned to play to their strengths, but I find that they are rare...generally, as a whole, gamers seem to tend to have ideas about who can tell whom what to do in which situation.
Enter one of the seven deadly sins: pride. It can be a gaming-group killer. A GM must often learn to swallow it, and a player who refuses to stand down starts a conflict that is difficult to administrate. After all, the first authority a player has is refusal to play.
Rule of thumb: People respect people who show them respect.
Games of pride can escalate quickly. Instigation comes both from within and without the game. Who answers to this? The GM? The players? Who has the authority to make a stand and declare a "winner"? When it is not merely a question of right vs. wrong, but someone who doesn't know when to admit that they're "beaten?" Who has the authority (and therefore, the responsibility) to handle the ensuing tension?
The common response is that the gamemaster has the authority, but it is paramount to understand that the investment into a game is mutual between the gamemaster and the players. There is no easy solution, but before making the GM the parent/babysitter, perhaps it is best that everyone involved has not only a chance for a decision that allows them to keep their pride intact, but an understanding that the shared power of group consensus is a much subtler tool than the blunt hammer of GM's fiat.