i sat in on guitar with the band at a cousin's bar mitzvah like 25 years ago. they invited me up, on request from the cousin's mom, the BL handed me his guitar and we played a few simple songs, they gave me a couple solos, it was fun.
that having been said, i would never DREAM of asking to sit in with a GB band, not then, not now--these people are at work. i might help bag groceries but usually i just let people do their jobs even if i know how to do what they are doing. i would also not ask to sit in with a band at a bar / club gig. if they invited me up, great.
but given the circumstances, i think your BL did one of two right things--he asked you if it would be okay. the second right thing would have of course been to reject the request.
that having been said, i would never DREAM of asking to sit in with a GB band, not then, not now--these people are at work. i might help bag groceries but usually i just let people do their jobs even if i know how to do what they are doing. i would also not ask to sit in with a band at a bar / club gig. if they invited me up, great.
but given the circumstances, i think your BL did one of two right things--he asked you if it would be okay. the second right thing would have of course been to reject the request.