As example windmill situation.
You can talk out bunch of goblins from attacking you. They all run away and you... gain nothing from it (other than avoiding combat).
"Now that sucks!" first thing most gamers would think right after. Reload. And proceed differently with killing every goblin.
And sucks it is, if game properly rewards only when you aim for killing anything that moves.
Now of course it still wouldn't be equal situation. Ran away enemies still will carry all their "loot" with them (with exception of unique encounters, where you actually might convince enemy party drop all their loot and gear).
But nevertheless you should be awarded equal amount of experience from resolving potential conflict nonviolent way.
