[tptacek]

I don't think it's about the technique. The "precedent" (set at least 3 years ago, when this was all announced publicly) involves the tradeoffs.

The technique comes into the picture because there is no technique for detecting tax fraud that makes the same tradeoffs.

I don't have any trouble believing simultaneously that we shouldn't have a "culture of automated state surveillance" and that it's OK to sweep image uploads for matches against known child pornography. Just like I had no problem with metal detectors, but do have a big problem with millimeter wave imaging.