The use of unmanned aerial vehicles (UAVs) in the conflict zones of Iraq and Afghanistan for both intelligence gathering and "decapitation" attacks has been heralded as an unprecedented success by U.S. military forces. There is a demand for substantially increased production of Predator MQ-1 and Reaper MQ-9 Digital Object Identifier 10.1109/MTS.2009.931865 drones and funding has been boosted to enable the training of many more operators. But perhaps there is a danger of over-trusting and overreaching the technology, particularly with respect to protecting innocents in war zones. There are ethical issues and pitfalls. It is time to reassess the meanings of discrimination and proportionality in the deployment of UAVs in 21st century warfare.