Well, no. You made the point that there's a difference between photos, still images that can be altered and footage that is essentially filmed in real time.
Yes, the chase scenes were fabricated, but people still got footage of them on dinky little cellphone cameras. And given this is New York, it's possible people thought there was an actual chase going on between police and some criminal.
Ergo, if you had Visser Three in Kafitt bird morph chasing Ax around in 2011, people might think it's a movie set, or they might think it's some undiscovered animal or mutation. It would be all over Youtube and in the news on CCV tapes.
It's the reason why Transformers Revenge of the Fallen loses a lot of it's credibility just ten minutes into the movie. A battle between Transformers in the middle of a major Chinese city and all the Internet has are static images on crappy cameras? Wouldn't happen.