» Mon Nov 19, 2012 7:40 pm
Here is a detailed explanation:
Picture this scenario: Upon entering Whiterun, vampires spawn on the other side of the town, far away from the player. Vampires are much tougher than NPCs, and therefore will quite obviously win. NPCs seem to be unable to determine whether or not they will be able to effectively combat their enemy, and therefore will rush headlong into even the toughest of battles. Now, all NPCs near the vampires will start attacking, but the NPCs will just be cut to ribbons by the vampires which are superior in every respect. All the while this is happening while the player is unaware of it, and therefore the player eventually overwrites their save, unbeknownst to the destruction that had just occured.
But suppose that the player WAS in fact aware of the attack. Would the player be able to the NPCs in time? I'd wager a guess at no. You see, as I said just, vampires are much stronger than NPCs and generally will kill an NPC in 1-2 hits. The player could sprint, use Slow Time, or even Whirlwind Sprint: It doesn't matter. Chances are, at least one of the NPCs will go down in the fray.
For towns within the Tamriel worldspace, the player simply has to be near the town for the attacks to occur. Therefore, vampires might spawn within the town and the player would be unaware of it.
These attacks happen frequently and given the often destructive aftermath, will, over a period of time, makes the towns and cities of Skyrim devoid of all life except guards and essential NPCs, breaking immersion.