Different countries have different views, and LAWS, on "public" photos. In the U.S. there is generally NO assumption of privacy if one is in plain view in public. I have been informed that the opposite is true in France. I suspect there is software, possibly even shareware/freeware that can automate the process of face detection and blurring. I'm pretty sure GoogleMaps and BingMaps have implemented such privacy processing in response to concerns voiced. Ultimately, it is the individual synthers decision how to handle this issue.