[fouric]

Resource consumption for low-accuracy voice transcription is trivial - think in the single-digit milliwatt range[1] for custom hardware. It would also be really easy to hide the resulting small amount of textual data in routine communications with the service's server.

You can't rule out audio transcription on the technical basis that "it's too hard" alone, because it's not too hard.

(for Google, that is - Facebook is constrained by the Android sandbox, but Google has their opaque Google Play services blob on almost every Android phone)

That's obviously not a reason to believe that it does exist - we'd only know that if a Google whistleblower stepped forward, or if someone reverse-engineered Play Services - but we can't rule it out on a technical basis alone.

[1] https://groups.csail.mit.edu/sls/publications/2018/Price_IEE...

[not2b]

Better to focus on the things that we have evidence that they are doing (and there is plenty of abusive behavior we know about) than to speculate about unlikely attack angles and say "we can't rule it out" (proving a negative is nearly impossible). Working that way just leads to focus on the wrong threats.