Has anyone hacked an F-16 yet? After all it is a computer controlled plane with comm links and everything a UAV has. The pilot would be a helpless passenger if someone got into the computer. How about an Airbus? No. Hacking a plane is something that only happens in movies. Jamming an old primitive radio controlled drone has happened. Big difference.
As one drone developer put it when asked about the danger of autonomous machines going haywire: It is only an issue if it consistently kills the wrong people. Then it's a product recall issue.