I do hear people solemnly say something like "I learned this from Barry Manilow," as if he learned the song at Barry's feet. It's a real letdown when I find out the song was learned from the radio. I think honesty is best - even a slight deception will make you end up with egg on your face. And then if you really do learn something direct from a legendary singer, nobody cares.
I have a friend who has sung with some legendary people, and she can rightly claim that she "learned this from Hazel Dickens," which is really cool. Trouble is, she says the same about songs she learned from records. So, it's hard to tell what's cool and what's not.
There's one song Big Mick sings, that he says he learned from Ed Trickett. That one is certifiably cool, because I was there when Ed taught it to Mick. Unfortunately, I didn't learn it.

Hey, I could say I learned "The Key of R" from Bill Day - except that I can't remember the tune he uses, so I had to make one up and use the lyrics in the Digital Tradition.

-Joe Offer-