The Folk process is predicated on:

1) misheard copying
2) artistic preferences, and abilities
3) current fashions
4) prevailing laws & politics (eg PC, racism etc)
5) copyright &/or its abuses
6) boredom and creativity
7) memory plays tricks
8) playfulness (eg shanties - skippers name in this boat)
9) others, please specify "..................................."

cat, pigeon, lob :)