Hi Michael,
The "Dixie" book actually draws a picture of quite balanced musical exchange among blacks and whites, because we looked at people who lived together in essentially the same economic and social conditions. But it would be wishful thinking to suppose that all musical exchanges have been on equal footing, with equal benefits to all parties. I'd think there's little argument that African American artists historically have gotten the short end of the stick in terms of material and social recognition, compared to whites who made a career using elements of known black tradition. Can this be called exploitation? Sometimes, yes indeed. But when amateur, folk-based musicians cover pop music (such as Snowdens vs. Foster), it would be strange to think of that as exploitation in a way implying harm to the other party, for obvious reasons.

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A final comment about Emmett as author of "Dixie": authorship is a tricky question for the remote past. Those who reject the Snowden thesis might want to look carefully at how professional minstrels came up with any songs they claimed to be their "own." Why would you suppose that minstrels were disconnected from oral and folk traditio--whether black or white--and didn't use it?