There will be a Nest in every Google self-driving car. I don't have any concrete evidence of this, but it's not that far-fetched.
Why would a car need Nest ? I am curious.
Wait, there's a proximity sensor in the Nest (thermostat, I'm assuming you're talking about)? What function does the sensor serve? And what is its capability exactly - it can detect a person within 10 feet - who happens to be in the same room as the Nest thermostat? Or?
It turns on the display when you approach (normally it's dark), and also tries to detect when no one is home so it can go into "away" mode automatically.