Vandalism, security measure, or something else?

I was in Tucson over the holidays. At the AFB there (Davis-Monthan), they
keep a lot of aircraft in storage. At the south end of the base, several
recent arrivals were parked near the fence. For some reason, the "U.S. Air
Force" markings on the side had been torn up.

Does anyone have any idea why this was done? There were eight or ten
airplanes, all the same make and model, all with the same kind of
defacement.

You can find a picture of one of the airplanes he
http://www.nwlink.com/~peted/Davis-MonthanAirplanes.jpg

(Bonus points for anyone who can remind me what kind of airplane they
are...I want to say C-141, but I could be way off base).

Pete