g1smd - 11:30 pm on Aug 13, 2008 (gmt 0)

There isn't "one" page format to be parsed. There's obviously results with different types of universal results, and there are results with images and maps in them. There are the "split screen" results, and so on, too. Not only those, but sometimes results have extra javascript code on the links for tracking, so there are a variety of different code sets to parse - and I guess Google might track whether a real browser is seeing the results as to how they handle this "additional stuff". They could also easily detect that you showed multiple UA from the one IP concurrently.