Matt wrote: However, I can understand the concept of all the treasure xp reward being spread evenly because it avoids interparty conflict. If a single player were to keep stealing all the time or steal huge chunks of the adventure treasure then things might get ugly. As a DM I would get annoyed if a player were to consistently screw over the rest of the group... but if it was a rare event based on good role-playing I would be less alarmed.
Interparty conflict would be a by-product. Two characters can come into conflict because one is "stealing" from the party or whatever, but that's a result of an in-game action that is a result of role-playing. In-game, someone is getting some coin. That is one type of reward and it has very little impact unless the reward is really huge.
My understanding is that XPs is a total reward for participation of players in the game. The focus on XPs from money it is the primary source that is split up, much like other games would split up total monster kill xps, rather than awarding just the "kill shot" which is garnered by a single player. XP passes from GM -> Players -> Characters. If a GM awards individual XPs for this type of action, its out of scope (where actual money value is "in scope") of the fairness of rewards. Even a single level difference at low levels can unset party balance.
Otherwise, literally, it means your best interests are served as a player, and also for your character, to light-finger as much as possible, regardless of what type of character you play. We might as well call it the Thief RPG.