The guys over at Google Sightseeing noticed  that the Google Streetview camera in Fairbanks, Alaska apparently got covered over with plastic bags, obscuring some of the images that were shot.
This led to speculation that some enterprising residents had perhaps purposefully obscured the cameras out of privacy concerns – though, that seems moderately unlikely to me since I doubt most people know what the car even is when it’s tooling around, shooting photos of places.
Another theory is that the bags were to protect the camera during rain for a while, and the operator forgot to remove it while shooting pics.
It reminds me of here in the Dallas, Texas area where we have cameras on a number of intersections, automatically capturing license plates when people go through on red lights. I’ve heard people talking about using special reflective mirrors or electronic devices which return a flash immediately, ruining the legibility of the surveillance cameras (though, I personally think the simpler solution is to just not pass through on red lights).
Undoubtedly, more people would use creative methods to keep their homes from being photographed by the Street View camera, if they knew what it was and when it was to drive by. As it is, I think the obscured images are just some sort of accident.