Does this have a precise meaning? I've wondered about it since I first heard the phrase used. It seems to be used to cover (maybe) all of the following:
I heard it on Whoever's CD and liked it, so I sing it
I saw Whoever sing this and liked it, so I sing it
Whoever said s/he didn't mind if I sang this
Whoever taught me how to sing this
Whoever said I don't need to pay Performing Rights on this piece
I can see that the phrase might arise from the days when singers sang from their own hoarded song lists, before the widespread use of recorded music, and maybe this does overlap a little into not singing other people's favourites at the club, but....
Does it have a specific, precise, meaning?
(And yes, I prefer the phrase "I got this from the singing of Whoever" for the first two options.)