I do not believe this was unsolicited. In fact, one of the creators is an Artist in Residence in San Mateo where you can find this so I suppose this particular yarnbombing is more like a commissioned building mural than grafitti.
I will have to think longer on it. I also gave some written thoughts about performance art. I remember being at the Louvre and seeing "statues" that came to life in the courtyard. I cannot remember if they were buskars or part of the museum experience. I DO remember enjoying them. Hmmm.