Why? Well, it could be to prevent counterfeiting. The camera shaking might actually follow a predefined motion pattern that authenticates the image. Or, if that sounds too ambitious, shaking the camera could also simply prove that they're not using a bluescreen, by showing that the president moves together with the background when the camera moves. As for the flies, again, that might be something they throw in there that looks like an imperfection but is actually required to authenticate the broadcast. Dollar bills contain little red and blue fibers embedded into the paper for the same reason. They look like little hairs that came from lint your pocket, but they're actually there on purpose to prevent counterfeiting.
What do you think? Am I giving our government too much credit? :)