Call Screening is done locally on the phone, the call audio and transcripts are not sent to Google.
They need to make the audio available to the user. Their text to speech engine never maages to get a decent transcript figured out. That or people are just yelling gibberish into the phone when I screen them. Until I can review the call audio I'll never know.
I very much want to believe this. But I can't. This is a sad state of affairs.