Wall Steet Journal: Iraq militants used SkyGrabber a 26$ software to intercepted live video feeds from U.S Predator drones. The U.S. military personnel in Iraq discovered the problem when they found a laptop of a Shiite militant which contained files of intercepted drone video feeds.
The capture of the feed was possible because the downlink between the unmanned craft and ground control in unencrypted. The solution is to add encryption to the system. The problems of adding encryption include a price increase on the drones and also interoperability problems between sharing of time-sensitive data within the U.S. military and with allies.
My comment is that this is a good security lesson to those that believe that unprotected data will be difficult to be discovered or that it is difficult to steal sensitive data which is transmitted without encryption.