It's not a hypothesis. It's a fact. I see dead NPC's all the time on my Xbox game. And dragon skeletons pop up all the time in places i didn't kill them. And it was said before the game came out that the world was alive without you there. [and no it wasn't removed] I don't think mods really count as there not hard characters programmed into the game from the get go
It's a fact which is utterly incorrect. That's not how the game works. Your xbox couldn't handle the amount of processing power which is required. My computer couldn't handle the amount of processing power which is required.
It's true that NPCs have schedules which continue without the player being there. That is not what we are discussing. Combat does not occur. For the combat to initiate the player MUST be in such a position that the computer performs the calculations necessary for combat. That's often because the player is in the same cell as the NPCs. The NPCs can leave the cell, indeed so can the player, and the combat will continue. Thus you don't necessarily have to witness the death of a character, or even any of the combat itself. You just have to be in the same locality at the same time.
Based on what you are saying, there is a large chance that an ancient dragon will attack any given walled town without the player ever having visited that city.
Mods do count. Because those characters are the same actors which have been programmed into the game from the get go exhibiting exactly the same behaviours. The mod just introduced more spawns than was present in vanilla.
And even if that's not true. you can't explain random dead townspeople, guards etc.
You can. You didn't witness their death, but that doesn't mean they weren't killed when the dragon attacked the town. This could occur if a dragon enters the cells surrounding Riverwood while the player leaves at the other end. The computer will continue to calculate the dragon attack, but the player will not notice the battle. Next time he goes to Riverwood, everybody is dead and there's a dragon skeleton lying on the ground. However if he never visits Riverwood, no dragon will ever attack the town.