Black hats will love this.
Google took it seriously because of the potential for bad press -- the company clearly is sloppy on testing and protecting users' privacy, an issue they don't want to bring attention to, considering Google aims to have hundreds of millions of these listening devices in people's living rooms, bedrooms, and even bathrooms in five years' time.
This person also had the contact info for Google PR, which changed the nature of the interaction with Google.