It is very common in science fiction films for autonomous armed robots to make life-and-death decisions - often to the detriment of the hero. But these days, lethal machines with an ability to pull the trigger are increasingly becoming more science than fiction.The U.N. Convention on Certain Conventional Weapons invited government representatives, advocacy organizations and scholars to a conference in Geneva this week to discuss the possible use of autonomous weapons systems in the future, as opposition against them is on the rise.