The Blurred line between War and Simulation

Enders Game is a recent film based on the sci-fi book by Orson Scott Card, ill explain the plot a bit. Earth has begun to be attacked by Aliens from a far of planet, these aliens are ant like and seem to have a hive like mind. The earths military forces have failed at stopping all there attacks except one in which one of the mother ships was destroyed causing all its "children" to die. There has been vast civilian casualties, knowing more about the aliens the army wishes to attack them as the best line of defence. They gather a number of kids with extreme intellect, these then run through trials and simulations to see who has the best mind as a leader and tactician.

The protagonist called Ender wins and becomes captain or something and has to complete the final simulation. In which he controls an entire fleet of human space ships. He has one change to destroy the planet in the simulation using this huge layzer gun however it has to reach the surface of the planet. There is a blockade of alien craft in its way, as if they knew what it did. Ender sacrifices half of his battalion to punch a hole through the blockade allowing the layzer to be fired and destroy the whole planet and so all the queens and so the whole alien race.

Once he completes the test he is then told that it was not a simulation and that he just won the war and saved the world. Everyone treats him as a hero, but he can not feel like one as he sacrificed thousands of lives to do it, and also had been having second thoughts about doing it after finding evidence to support that the Aliens were sentient creatures that couldn't talk but could communicate telepathically. They had only gone to earth in search of water or a new home world as theres was about to blow up i cant remember which.

Anyway the point is, at some point in the future war and simulation may be so similar that they cannot be told apart by those who fighting in them. So if you cant tell when your fighting real enemies or simulations, who is held culpable for the killing. Future casting here, the idea that the best gamers would be in control of real world military technology such as a drones or robots to fight the enemy, (like in Gamer) but may just think there playing a game so would not feel anything toward killing but that they are succeeding in their game.