Not exclusively, Alan, but folk music and dance did have a different meaning for them, I suppose. I remember the band Folklaender singing a song about travelling artisans (?) with all those destinations that no one living in the GDR would be allowed to travel to, giving the song a subtext it didn't have over here.

Anyway, another link for those who'd like to find out about the range and variety of folk music in Northern Germany: LAG Folk Schleswig-Holstein