Not necessarily true. We had a lightning strike during a severe storm at Miami which damaged an electronic system meaning we were not RVSM capable. Having taken 2 1/2 tonnes extra, we were able to descend to 28,000 for the non-RVSM Atlantic crossing (US wasn't RVSM then). Flight Planning at London rerouted us the quickest rerouting at that level (over Liverpool instead of Lands End), and we made it back OK, admittedly with minimal fuel. Had the autopilot been not available, I see no reason to cancel out. It makes a lot of work, but you are a pilot to fly the aeroplane. The autopilot is an aid, just like any other, like a flight director. It is not the be all and end all of flying. I would have a lot of explaining to the Flight Manager why we threw 80 tonnes of fuel overboard because we couldn't handfly for 10 hours!