Well, Gentlemen, the key word two posts back is "adhering".
In very-cold temperatures with cold fuel in the wings, sweeping the snow away in various spots to ensure that is was not sticking and that there was a clean, uncontaminated surface beneath allowed one to depart, both from a legal standpoint and from an airmanship one.
However, when the outside temperature is hovering around or just below the freezing point( or if there is any possibility of the fuel uplift raising the skin temperature to near freezing), then my carrier didn't even bother checking using the tactile method described above: they ALWAYS deiced.
What hasn't been mentioned in this thread is the pilot that decides that it is all melting on its own and departs without considering what the windchill does during the takeoff roll.
Based on the snow adhering to the flap canoes and the outer fuel cells which receive the fluid recirculating from the IDGs, I think it's a no-brainer that this crew should have elected to deice.
My comments based on 40+ years of heavy-metal operations in the coldest-country on the planet...