Ah yes, I remember the YT sleeve note now you remind me (I have the vinyl somewhere at home).

As for why people have (possibly) done it, maybe just for the fun of fooling other people, in the way that the perpetrators of hoaxes do (e.g. the Piltdown Man). Ms Piepe must have been amused by the FD's reaction when she first sang the songs to him. But I assume she would have told him after proving him wrong, as she had a point to make to him.