When this came out I read it in an academic "this won't ever happen to me" sort of way.
Today I went out flying. We had sub-freezing weather and fog filling the Clackamas river valley in Estacada, where my RC club flies.
I could see the ice collecting on the lines. It wasn't bad enough to affect performance (at least that I could tell), but it was definitely there. And after I landed, I had ice on the leading edge of the wing and landing gear, much like your picture.
And as I was flying, the lines thrummed, with this low frequency hum that I've never experienced before with control line flying.