"The term does not cover composed popular music that has been taken over ready-made by a community and remains unchanged, for it is the re-fashioning and re-creation of the music by the community that gives it its folk character."

The problem with this is that the changes come about as the song is passed down through the aural tradition. It is learnt from singers within the community, not from the orginal. This can only happen if someone learns it in the first place; someone who thinks "That's a good song. I'll have that". The Plains of Waterloo must have been a contemporary song less than 200 years ago.