If the wings are de-iced extended that would require a lot of re-certification/surveying of de-icing stands/areas where you typically would not be/taxi alone. As the whole point of the folding wingtips is to use existing airport infrastructure without modifications, that would not seem to make sense. I'd assume it would need some testing on how fast type II/IV fluids flow off the retracted wingtips. The FAA might be less inclined to wave this through quickly these days, however.