Well, interestingly songs have been lyrically - and melodically -revised even after they have been recorded.
I remember being shocked to hear Hugh Jones's changing some of the lines in his marvellous "Marco Polo".
Likewise, Bruce Springsteen's much loved song "Thunder Road" seems to have been completed in the recording studio as earlier versions of the song ( which can be heard on bootleg recordings) don't even contain the words thunder road.
My problem with the words, in the line in question, is that they suggest that the writer of the song didn't really get inside the heads of the characters that he created!

And as to the "it's not your song to change", well, if it's out there, it can and will be changed!
It's called the folk process, you know!