Trev: as Law said, that would be true were it a shadow. But reflections do not behave like shadows. They behave like reflections. That is, they behave like windows into a parallel universe - holes, if you will, that, rather than show what's on the other side, double back upon themselves so that, were you to fall into one, you would end up back where you were. Going into a reflection is sort of like exiting through an entrance to where you are. Or entering through an exit of where you wouldn't be.
See any of the above posts for the more laymen phrasing.
(It's why, if you set a can or a bottle on a glass table, the reflection doesn't squash, but seems more like a continuation of the object, or the object sitting on itself upside-down.)
