Sometimes, someone is.
This wording is misleading, because it sounds like someone is listening through the device as the speech is being picked up by it, but in fact it's recordings.
There is no legally binding lock out time because there doesn’t need to be. Live-listening is impractical at scale and also worthless for what the article is describing they do with the data.
Remember, this work is being done to make it so humans don’t have to be in the loop.
Because there is no value in doing so. A person could collect all the spare change thrown into fountains at shopping malls, but they don’t.
Whether you consider that “actually watching” is a matter of opinion, but your ability to process and take action on any of the clips is certainly diminished.