'and the band played waltzing matilda'

'the ballad of st anne's reel'

In a sense, every "Come all ye..." song is kind of a song within a song. They set up their stall right at the start as a song telling a tale; it's a distancing effect.

If you wanted to score academic cred points, you'd describe it as a Brechtian alienation technique. Or 'postmodern'.