https://www.siliconvalley.com/2019/09/23/google-assistant-workers-will-again-listen-to-your-audio-if-you-approve/

Google workers will listen to audio snippets of people speaking to its digital voice assistant to help improve the product’s quality — if users give the company permission to do so.

Alphabet’s Google paused all human review of assistant audio in July after a Dutch contractor leaked some clips to a journalist, who was then able to identify specific people on the recordings. On Monday, Google said it’s bringing back human reviewers, but adding a new set of precautions to protect customers’ privacy.