Huh. That's not something I think of as a Christmas carol at all. It is an old folk tune (It's the alas that sets the tone of it: "alas, you do me wrong to cast me off so discourteously" or something like that) -- but it's something I always think of as a summer tune, along with hearing it for icecream. And, yes, we would occasionally buy ice cream from them, but usually when out somewhere -- I don't remember them driving around our suburbs often.