The 'your character must believe functionaries because after a lifetime of experience they have never been wrong' argument can be easily avoided, if you adopt a different way of perceiving your relation to BM.
Imagine there BM is an actual working world in another dimension, and the only way we perceive it is through this website. The only messages that manage to get through to our side are the messages that are true. We never learn about the fake messages.
It's not hard to imagine your characters to be busy doing daily things even if you don't roleplay them doing it. It is equally easy to imagine that these characters are bombarded by fake messages all the time. Where you as a player receive a single scribe note, it's not hard to imagine your character actually received a dozen, had them verified (?), and in the end concluded one of them was right.
Looking at it this way I think it is quite easy to continue believing in the game mechanics, but also for the player to decide not to believe them when suitable (such as for RP reasons, to keep things interesting, or to gain an advantage).
