Even your comment is based on the condition that “you believe all of Google’s descriptions of their procedures.”

The car has to travel during the bright of day given the shutter speed necessary to grab crystal clear images at 30mph. Also, we’re more likely talking about residential connections, because businesses are more likely secured than open. They also said the user had to be actively using the connection.

Yet, they gathered 600GB of data from people at home, during the day, likely on weekdays, actively using the network, and in miliseconds of exposure?

That seems like a staggering amount of data given the relative difficulty of meeting all of those conditions.

It’s far more believable that, as the other commenter says, they were just passively recording network traffic.

To me this says more about how difficult it is to comply with privacy regulations and how people go nuts every time there’s an innocuous problem like this. Really, there’s every reason to believe that this was accidental and that nobody was harmed.