Each one of these could be a potential missile used against us. This seems to be exaggerated. Wouldn't you need a drone on American soil, already right next to the target, in order to crash it by sending falsified GPS coordinates?
Unless one gets downed abroad and reprogrammed.
http://www.defensenews.com/article/20111204/DEFSECT01/112040...
edit: ( I think the real concern in this situation would be reverse engineering with an eye to finding vulnerabilities to be exploited in other drones, not so much reprogramming the one and only they have )