Originally Posted by
Kish
Cart before horse. Your reputation gives you a bonus or penalty to reaction checks. If your Charisma is just on the edge between two results, then the reaction you get will be different depending on whether your reputation is 8 or 12. But if your Charisma is 3, everyone who is making a reaction check will hate you whatever your reputation is.
(Which is not to say there aren't separate pure-reputation checks in the game: Jaheira's response to Elminster asking whether she was right to stand with you, for example.)