NPC reactions have not been implemented yet. Currently an NPC has to call for help to trigger anything (and they are far too forgiving of 'accidental' attacks).
I'm really looking forward to this being fixed. It'd be even better if NPCs actually reacted to your casting attack spells and/or breaking doors/containers (even those that aren't considered "owned") nearby.
But at the other extreme, being murdered by a guard for stealing a piece of parchment is wayyyyy overkill. Taking (especially low-value) items shouldn't ever trigger a kill response as the first resort. This happened to me in the harbor warehouse. I know the guards in that area are on high alert or something, but still... that's cray-cray.
