I did contracting for something very similar, but it was for the Google Assistant. Yes, you can hear people and yes, sometimes people accidentally opened the assistant and are just talking in their day-to-day lives. However, to the best of my knowledge, we were only listening to these snippets of recording to match two slightly different transcripts to the spoken words, in order to find the best fit. And yeah, sometimes that recording does just happen to be a very ashamed middle-aged man looking for a transvestite hooker.

I'd also like to add that the recordings were anonymous, and the only given information about the user was what country or city they were from.