Q, I agree with you about that. I sing a version of this (the Marlene Dietrich version) and think the line that suggested the camp-follower thing for is this.
"Give me a rose to show how much you care,
Tied to the stem a lock of golden hair,
Surely tomorrow you'll feel blue,
But then will come a love that's new
For you, Lili Marleen,
For you Lili Marleen.

Now since the song is from the perspective of a soldier singing about the girl he loves that he met under a lantern outside his barracks, that line always struck me as a bit puzzling. Why would a soldier singing about his girlfriend say that?