Fake books come in a wide variety of varying quality. Some from what I've seen when read and played as written acually make the music sound faked, while some come with two or three differant versions of the same tune showingfamous solos that have been played throughout the years.
Band arrangers are very protective of they're arrangments. I've heard some complain that they're pieces have made it into a fake book. But I think they are secretly proud cuz it means they have made an impact in the world they move in. It's like the closest thing to the oral tradition you can get it the band world.
I have been at times in deep appreciation of of a good fake book cuz I am sometimes asked to sit in with bands where I am not familiar with the repertoire. Also, fake books have at times shown me some very nice substitutions for chords that my ears might have told me to play and would not be wrong by jazz standards but the guys in the band all kinda look at ya sideways and know what world you are coming from. Theres no hiding some things.