I don't really understand your question.
I usually try to give myself a legitimate reason to suspend disbelief. Things working differently in the counter-factual world are not distracting, they are just accepted as premises. In some stories things are explicitly not presented as premises of the world still seem to happen.
I'm not invoking "acceleration magic"; vampires just move very fast.
I like 'vampires just move very fast'. In terms of what the 'just' entails it seems that, for example, "just have the ability to output large amounts of power from the muscles and thereby cause acceleration through the application of force upon items in the environment" would be a rather ungainly. A somewhat more nebulous 'just' fits better for this kind of story.
This was prompted by thinking of the optimal way to protect a human passenger in the event of an automotive accident. If I was a lightweight version of Cameron - super strong and super fast but otherwise operating under completely standard physics - then I wouldn't choose Edward's passenger protection strategy. There are all sorts of other options which would require lower concentrations of force on the human's body over time and space. But with the kind of strength and speed exhibited by the vampires in either Twilight or True Blood the approach seems to fit perfectly. They are 'just' really fast, for a specific kind of 'just'.
Vampires do not exceed the speed of sound. They are not even as fast as ordinary airplanes or really fast cars, or they'd have no reason to use either barring subterfuge purposes and a fondness for vehicles. So no, no sonic boom. But over short distances, even going 100 mph would mean crossing a football field in a third of a second, if my back-of-envelope bad-at-math calculation is right. Bit quick for a human to follow. (They don't take any appreciable time to start up and slow down when they aren't trying to.)
Vampires that don't care much about loo...
In the vein of the Harry Potter and the Methods of Rationality discussion threads this is the place to discuss anything relating to Alicorn's Twilight fanfic Luminosity. The fanfic is also archived on Alicorn's own website <strike>(warning: white text on black background)</strike>.
Previous discussion is hidden so deeply within the first Methods of Rationality thread that it's difficult to find even if you already know it exists.
Similar to how Eliezer's fanfic popularizes material from his sequences Alicorn is using the insights from her Luminosity sequence.
Spoilers for the fanfic itself as well as the original novels need and should not be hidden, but spoiler protection still applies for any other works of fiction, except for Harry Potter and the Methods of Rationality chapters more than a week old so we can freely discuss similarities and differences.
EDIT: Post-ginormous-spoiler discussion should go to the second thread. (If you have any doubt on whether you have reached the spoiler in question you have not.)