If it's a traditional folk song played by a rock band, it's still a traditional folk song. If it's a contemporary folk song played by a rock band, it's a rock song. If it's somewhere in between a traditional folk song and a contemporary folk song, you get to choose, just like you get to choose if it's closer to traditional or to contemporary.

Spleen Cringe, I've always thought that even when Malicorne wasn't using electric guitar or drums they were better at doing rock versions of traditional songs than just about anyone. Great band!