Of their pre-established remit
Of course, some would argue that this sort of service should be free and, heck, well it would be nice but it is not exactly on our list of required MMORPG features is it? Players can not change side in game and thus NCsoft has established this service as being an additional extra for the game, something that is outside of their pre-established remit. SOE, on the other hand, allows characters to change faction in Cronous gold via quests so if they started charging for it, all hell would undoubtedly break loose.