We’re ignoring the possibility that there was a time traveler, who planted the film in an effort to discredit believers in time travel.

I am not teaching Hume on miracles for the foreseeable future, but if you are, here is a doozy of a toy example to make you with it and hip:

http://www.youtube.com/watch?v=KBhN4P0mehM&feature=related

Time travel may be possible, but epistemology is a bitch.