Digressing from the thread slightly, the above post reminds me of an interesting tale I heard of a large CTR about 100nms south of Sydney Intl that was controlled by the RAN at NOWRA... through the zone ran a low level VFR route, along the largely deserted coastline. The story goes, one day an aircarft checks in (registration only), and the busy controller assuming its a light aircraft issues a clearance on the VFR route not above 500ft. A while later that callsign calls changing to Sydney Approach... job done? A few hours later the NOWRA controller get a phone call from the pilot... who had been flying a 747 on a cargo or positioning flight, thanking the controller for the best clearances he had ever received!!!
I don't have first-hand experience of this, but it comes from a reliable source... and as they say "never let the truth stand in the way of a good story"... anyway back to the MSD debate.