Hold That Ghost

So I checked into The Marseilles Hotel yesterday, and although it's not the nicest hotel in the room (your typical South Beach flea trap), I was more than a little bemused to see this Post-It Note attached to a little purportedly inspirational poem on the wall:
I don't know what picture they are talking about, but I detected no ghost activity--not even actress Alice Ghostley. (The next door room's closet is behind the [thin] wall behind the bed, and it's easy to hear hangers clinking about in the morning. Perhaps the ghosts offer a valet service.) Fortunately, there has never been any definitive evidence that there are such things as ghosts. But even if there were, there certainly, as far as I know, has never been a reliably documented incident of someone being killed or injured by a ghost. So there's not much to be scared of.

I do have a question about ghosts, though. Even if we grant the premise that there is some kind of energy that comprises the soul and that it can linger on Earth after we shuffle off this mortal coil, and even if we assume that it can take the physical form of the person who died, why, oh why, is it wearing clothes? Ghosts always seem to be "seen" wearing Victorian garb, or fancy dresses (never flip-flops and tank tops, thankfully), or whatever. What would the mechanism for that be?

And another thing. Those silly ghost-hunting shows...they always seem to be using infrared cameras to capture "heat traces" or whatever, which is supposed to be evidence for ghostness. As Ken A. explained to me (as he has used infrared cameras), in order to pick up anything, you need to calibrate an infrared camera using a coefficient that has been determined for the surface generating the heat (which is what infrared radiation is). How do you calibrate an infrared camera to take into account the surface of a ghost? Because unless you do this properly, whatever you pick up on the camera could be anything and not especially reliable.