I do, and maybe that mindset has been brought about by the fact that it's what actually happens. The oil operators have no top cover, no fixed-wing aircraft, so therefore it's DND. When the Cougar crash occurred, fortunately there was a Provincial Airlines ice-spotting plane in the area. It provided a degree of top cover, but the DND top cover arrived very quickly, relatively, from Greenwood.
In the course of this, I have seen top cover and overall direction as coming from DND and first response as coming from the oil operators.