Players versus teams & making war versus making peace

[hooj]

I've been going through the SDK code, and I'm somewhat fuzzy on what the distinction between players and teams is. I obviously understand it from a gameplay perspective, but the way the engine actually handles it is rather baffling. For instance, CvPlayerAI::AI_doPeace() appears to determine if an AI wants to make peace with another player, but CvTeamAI::AI_doWar() seems to make the decision to go to war. So Team AI makes war, but Player AI makes peace? What's the reason for the distinction? What's the rule-of-thumb for belonging to a Team versus belonging to a Player?