Hi.
Since the genre I'm on is mostly classic rock, and since I doubt that my band-mates (with one exeption

) use any notation at home and during these 5 or so years we've been together have
never brought any to the rehearsals, it'll be safe to say they wouldn't know.
Treble clef (G-clef), the same deal, most probably no idea.
Drummer probably knows the "neutral clef" though, since he's taking lessons and can read some percussion notation.
And why should they? They'd have no idea what the dots with lines mean anyway, let alone figure out how to play them.
That doesn't make them any less talented or enthusiastic, but obviously can be a bit annoying at times.
Music, any music, has the written language as well after all, and communication without it can get way difficult at times

.
Regards
Sam