That’s on the same level and also entirely different, but the same..... Drummer, bass, and other guitar player in our rock band also play in a band with a 5-6 piece horn section...they regularly need subs in the horns, but the defacto leader of that horn section is an ass hat and won’t accept any subs that don’t read charts, because you know everything is in the charts. Which is a shame because the guy that’s most often available, who also happens to be one of the most badass sax players in town, doesn’t read music, never has....and he’s a mind blowing improvisor. It blows me away that these people need the charts for the same fucking songs they’ve played near weekly for literal decades, absolutely shit themselves if the “chart book” is not there....hmmmmmm