Well, if fakers make the effort to do the math (and physics), more power to them. It just makes this kind of video forensics a more interesting challenge. :)

Here's another example of a physics based take-down (by Rhett Allain) of that eagle lifting a baby video that was doing the rounds. http://www.wired.com/wiredscience/2012/12/eagle-picks-up-a-k...