It is an *insulator*.  That is what counts.  (I would expect it
is high density plastic, but it makes no difference and it might well
be a glass.)

Because it is physically attached to the CCD, which is charged.

True; but it might take an infinite amount of time before
anything on the other side of the universe moved enough to
measure.

Three centimeters might as well be an infinite distance given
the short period of time required to clean the sensor.

That is almost certainly true.  When using forced air, it
absolutely is true.  But even if someone is actually swabbing
the sensor with a damp cleaning tool, the air movement resulting
from movement of the tool is going to be many times more
significant at 2 or 3 cm than the static charge will be.

The static charge is significant because anything that actually
does get blown onto the sensor (or close enough to actually be
pulled in by the charge) is going to be *held* there.  No
bounce...

I'd expect a mm or two, maybe even a bit more.  Two cm, no.

I can assure you it is *not* a myth.  Anyone who maintains
electronic equipment can attest to it.  The higher the voltage
on components, the more dust collects on them.  Areas that have
good grounding to discharge electrostatic buildup will be
cleaner than insulated areas that have even just a few volts (or
for that matter no voltage at all if there is air movement)
available to supply a charge.

Poly plastic in contact with *nothing* but dry air will pick up
enough charge to attract dust!  In fact, the way the pink
anti-static plastic commonly seen as packaging material was
discovered was because a young fellow hired to wash plastic
"sample" containers was "cheating" by not rinsing them off after
washing.  In a place where thousands of them were in use, this
showed up very quickly because if they weren't rinsed they
didn't get dirty nearly as quickly.  Suddenly the work load for
the dish washer dropped dramatically.  They were being used by a
bunch of engineers who made plastics, who noticed the huge
increase in cycle times for the containers that happened when
this new guy was hired.  So they investigated.

The guy was washing the containers and putting them directly
into drying racks rather than rinsing them the way he was
supposed to do it.  That left each container coated with
automatic dishwasher soap, which is a very good water
dispersant.  It allowed a film of water to remain on the
containers, and that caused static electricity to discharge.  As
a result, no charge and much less dirt attracted to the
container from the air.  Hence it took 2-3 times as long before
it needed to be washed again.

The story I heard was that they fired the dishwasher, of course.
(Then they hired him to do something more appropriate to his
talents... :-)

The engineers immediately saw "anti-static plastic", their eyes
rolled like cash registers, and they stayed late and mixed up a
batch of plastic.  They assumed it was going to take many tries
to get it right, so they wanted to mark the batch with something
to let them know which batch was which.  All they could find
that night was some lipstick in the purse of a wife who had come
to pick up her hubby.  They tossed it in.  It worked.  It worked
very well.  They laughed about the exact terminology that should
be used to describe the color (sexist pigs that they were, it
referenced the female anatomy), and actually mixed up the
initial commercial batches still using lipstick for coloring!

Fortunately, Nikon sees the foolishness of adding all these interlocks.  The
other issue is a consumer would have to waste 15-seconds of their time to
devise ways of circumventing these interlocks.  This also would be a pain in
the a.s when you have to clean the old sensor.

Agreed!  Leave well enough alone.  Plus, manufacturers go by the theory that
if you are buying a dSLR you should be smart enough to read and comprehend
the instruction manual.

Rita

<G>

David