I don't have a link at hand but yes, I believe I've seen this done fairly well somewhat recently. Modeling the actual faces might give false positives as someon

I don't have a link at hand but yes, I believe I've seen this done fairly well somewhat recently. Modeling the actual faces might give false positives as someone else said, but depending on how strongly the blurring/pixelation is performed, what the movement of the camera is, and how many frames you have access to, there's a lot of information in those blotches and you can reconstruct arbitrary images from underneath.