But have you ever heard anyone claim that they have seen a naked ghost? I'm left wondering how these disembodied spirits have some way of remembering what clothes their corporeal forms used to wear, and indeed how they choose from the wardrobe that must have changed throughout their lives.
You might argue that this is no stranger than the concept that the ghost's former self changed its appearance throughout its life, but that somehow the apparition has chosen a snapshot in time - presumably normally at the point of its final demise.
Maybe they keep the clothes that they wore at the same time.
Or maybe there are just no ghosts and the people who have the requisite imaginations to conjure up such an image in their minds have no trouble conjuring appropriate-looking attire as well.