Why are people so gulible. If they had a Fallout 4 you would probally hear about it, or since your on the forums there would could be more Fallout 4 traffic resulting in its own little category. Then on the video you could have seen Bethesda's name on it, and it would look updated. Since its their first teaser trailer they don't tend to show gameplay so the graphics would look better than Skyrim's as it will most likely use that engine. It would have been some cinematic most likely like Fallout 3's sugar bombs, or New Vegas's ED-E, no art styles from in game or poor gamebyro graphics.
Then there is the point that San Francsco is deep in NCR territory, and from some tiny clues most likely controlled by the Shi.