I know of three examples of this interesting phenomenon. Can anyone add more?

1. The second stanza of “The Wreck of the Old 97”:

Then he turned around and said to his black, greasy fireman,
“Shovel on a little more coal.
And when we cross that White Oak mountain,
Watch Ol’ ’97 roll.”

On at least one of this albums, Mac Wiseman changes this to “big ol’ greasy fireman”. Of course, the original text has nothing to do with race. Any man who spends his day shoveling coal into the open door of a furnace is going to be black from the soot and greasy as soon as he works up enough of a sweat to mix with the soot. Granted that some firemen may have been black to start with, there’s no reason to suppose that this one was, or that it would have made any difference to the song if he were.

2. One couplet of Bob Wills’ rather disjointed “Take Me Back to Tulsa” reads:

Little bee sucks the blossom, big bee gets the honey,
Dark man picks the cotton, white man gets the money.

On The Archive Series, Vol. 2, Dan Walser changes this to:

Well, the little bee sucks the blossom, but the big bee gets the honey,
The little man raise the cotton, but the big man gets the money.

3. One of Johnny Cash’s best-known lines is this, from “Folsom Prison Blues”:

I shot a man in Reno, just to watch him die.

On Kindred Spirits: A Tribute to the Songs of Johnny Cash, Keb’ Mo’ changes this to:

They say I shot a man in Reno, but that was just a lie.

I can see why a black man might not feel entirely comfortable singing the original lyrics, but the change wrecks the song. It would have been better to pick another song if he couldn’t do this one ‘straight’.