Someone call a tailor!

Accepting the fact that vampires have no reflections, how come in many instances, when they show the obligatory mirror scene, we aren't treated to something akin to the invisible man, where we only see the clothes hovering in the air, filled by an unseen being? Why, instead, are we shown the inevitable blank mirror reflecting only the empty room and/or living person about to be bitten? Do vampires wear special clothes, or are their clothes made from vampires (which is really kind of a morbid thought, but we are dealing with vampires here)? What's the deal?

(It's probably just due to the limitations of special effects, but still, it's been kind of bothering me for some reason.)