Probably a result of the iPhone camera's rolling shutter, combined with a very brief flash of light. You get similar craziness when you try to take pictures of objects moving at high speed, like airplane propellors:
I used to do a lot of work with collections of digital images taken outdoors under all sorts of conditions, not entirely unlike what I suspect the raw Google Streetview data is like.
Pictures with that particular image artifact that weren't a message from the gods. They were an annoyance. A constant annoyance.
http://www.blogcdn.com/www.tuaw.com/media/2010/08/blades-128...