It seems as 'smug hindsightish' to berate the early singers for getting it wrong, as it did when Harker et al dismissed Sharp, Kidson, Broadwood.... and all the pioneers, without whom we wouldn't be talking to each other.
Something to keep in mind during this discussion.
I really like to know how songs develop over time, and the contribution each singer makes along the way. The claim by some that what they sing is exactly what one particular source sang has always seemed fallacious to me. Frank Warner may have been one of the few singers/collectors who had the talent to record and render a song close to what he originally heard but even Frank filled in the blanks when it came to "tuning up" the melody (some of the source recordings are definitely of singers past their prime as singers) and forming "composite" songs from separate sources.