I think the way to go about preventing this sort of thing would be to select the kind of things that should gain the player rewards. And which things remove them from him.
This is based upon Blackstream''s thoughts.
Suppose we have a Mr. I. N. Joykillen, new to the town. Some rumour that he is here to stop the evil goblins (shock!) from overrunning the village, by destroying their evil leader (shock again!), is passing among the townsfolk. Joykillen, after a brief chat with the locals, decides to enter the dungeons (oh the pain) and slaughter all the goblins in his path to the leader.
And this Joykillen does. As expected, his battle experience rockets upwards as he cuts down, kills and generally annihilates all the little green creatures in his path.
But his respect for life drops. He now sees no problem in messing with the blacksmith, maybe threatening him for a new weapon. These new options open to Joykillen. And he uses them. He likes them. As a direct consequence of such, he loses more and more respect for his kinsmen. And his kinsmen start fearing him.
What happens now? Does the town plot an assault on Joykillen? A strategic ambush, perhaps? Maybe they summon a mystic mage, one who Joykillen has no chance of competing with?
Let me take this down a different road. He can threaten the blacksmith. The blacksmith knows it. The blacksmith starts feeling uncomfortable around him. He tells the rest of the townfolk. They start losing respect for Joykillen... and, likewise, plot to make him feel less at home. Does the local healer now refuse Joykillen treatment? Does the tavern owner not tell him gossip? How can such a ruthless killer be welcomed into such a warm and loving society?
Perhaps he is exiled, never able to perform heroic deeds again?
The RPG is an untapped resource. I want to see this change.
The_Minister1C3-D3M0N Interactive