resumes have launched more, uhhh, creative fiction than anything since humans learned to lie about sex.
if you've sat in with a noted band and acquitted yourself honorably (the litmus test would be if they'd let you sit in again), i don't see any reason not to list it. i carry a sit-in session with the duke ellington orchestra on my resume because it was a significant honor and because i did well enough for mercer (duke's son) and most of the horn section to come back to the hotel after our respective gigs (i was in town playing with my own band) to get uproariously drunk and play cards all night.
