To me that quote sounds more like a polite way of saying they definitely won't reveal to callers that they are talking with a bot than them taking the concern seriously.
Some of the conversation examples on the blog page where they invent a sort of story for the caller ("I'm calling for a client") would fit that theory.
If they can get a way of saying "I'm a bot" without people hanging up the calls, I'm all for it -- otherwise, "I'm calling for a client" or similar is the best for everyone involved (assuming everything works).
Businesses also need to have a way to report problems to Google, like if they are getting spammed by Duplex or want to opt out.
I'm prejudiced against talking to bots because they're bots. They don't have empathy, whereas from voice interaction I expect a human I can relate to and desire to help and be courteous with. It's a fundamentally different type of interaction and I will be annoyed anytime that one is confused for the other.
Of course, if they screw it up, they'll burn that terminology too.
> The Google Duplex technology is built to sound natural, to make the conversation experience comfortable. It’s important to us that users and businesses have a good experience with this service, and transparency is a key part of that. We want to be clear about the intent of the call so businesses understand the context. We’ll be experimenting with the right approach over the coming months.