"Many ballads were collected without tunes anyway".

At the time that many of the ballads were collected, there was no real interest in the tunes - the collectors, and those who were likely to buy their publications, were only interested in the words - 'Ancient Poetry' - which is why many of the old collections are so frustrating to many of us today. Some collectors, like Alfred Williams, actually felt that the songs shouldn't be revived as songs, but felt that the words should not be lost. Strange isn't it, when the main focus of the collectors around the turn of the 19th/20th Century was, generally, the melodies of the songs they collected? To me, as a singer, I find both attitudes immensely frustrating at times, but the work of Bronson and others makes up for it to some extent.

I doubt that many of those who collected without melodies chose not to do so because the tunes weren't very good, although later collectors may have rejected certain songs for that reason. If collectors had wanted to collect tunes with the words, they would have taken someone with them who could take down tunes by ear (as Baring Gould did) - not an easy skill for anyone. So I suspect your speculations are unlikely.

You may be right, Diane, that those are the reasons that singers use(d) different tunes, either their own or others, but it may simply be an indication that they wish to make the songs their own rather than slavishly copying others, or they don't remember or misremember the tunes they originally heard, i.e. what is usually called 'the folk process'. It could just be a matter of individual creativity; sometimes the variations were anything but minor!

Barbara