Google Street View's privacy enhancing technology?

With Google's recent launch of Street View in Europe and imminent photographing of Canadian cities, I thought I'd do some quick looking around at how effective their "face blurring" technology may be. It only took one minute of wandering around London and I was able to see where it might fall off the rails.

In this particular image, the anti-war protesters are recognizable but - THANKFULLY - the image of what's probably George W. Bush has been blurred out. But not blurred to the point of non-recognition.

Google: You've come a long way, baby, but there's work to be done.