Come on, I'm sure Google's privacy policy allows them to listen to audio with no metadata in order to improve their service. The team is responding to the public leak of the audio, which is a violation of Google's privacy policy.
> the security and response team activated because someone disclosed that they do this
They're not chasing down a whistle blower for notifying the public that human transcription takes place. That information was already in the public domain in Google's privacy policy. The team is investigating the source of the leaked audio files, which was a violation of user privacy.
