Hmmm....
I wonder what level of systems redundancies are built in to these infernal roboplanes? Steve Fossett's Virgin Atlantic Global Flyer only had about 15 minutes flying time available after its single generator failed, but with a human pilot at the controls was able to land safely.
I doubt the same outcome would have happened had it been an unmanned aerial vehicle. Which is yet another reason why these damn things should only ever be permitted to be operated over sparsely inhabited areas.