If some talented Aussies with a little money can do this, imagine what evil people with unlimited money can and will do, and have done.
The Viral Experiment: Fake footage fools worldwide audiences, racks up 200mn views (VIDEOS)
https://www.rt.com/viral/352183-viral-experiment-fake-footage/?utm_source=browser&utm_medium=aplication_chrome&utm_campaign=chrome
https://www.youtube.com/watch?v=ccENfRThXOk