A slight correction: bluegrass guys have NO sense of humor!! I was jamming about 15+ years ago with a bunch of blugrassers at an open mic. I started with my guitar into a BG version of Roger McGuinn's "Mr. Spaceman" and one bluegrass "bigot" walked off in a huff!! I'm surprised he didn't say "Bill Monroe don't do that song!".
Bluegrass banjo players (at least from personal experience) also desire to pick a fight with anyone who suggests slowing down a song. Just my personal experience with bluegrass "bigots"!!