I don't know if anyone else has ever noticed this, but lots of street view pictures will have random face shaped blurs on walls and such. My guess is google has

I don't know if anyone else has ever noticed this, but lots of street view pictures will have random face shaped blurs on walls and such. My guess is google has set a very low false-negative threshold for face identification, and are thus willing to tolerate blurring lots of non-face objects (which isn't really much of a loss, anyways, and definitely tolerable if it means the difference between every real face being blurred and missing 1 out of 100).