Here's the full WiFi language:
Quote:

What information do you store and how do you keep my data safe?

To provide the Nest service, we store your account information, the answers to the initial questions used to set up the device, your Wifi Password, and three-weeks worth of sensor readings and schedule. All data is password protected and cannot easily be accessed. You can delete the information on the Nest device by resetting it to the factory settings.

We also store PII about your use of the product, including sensor data and your inputs from mobile and other devices on our cloud servers. We use industry-standard methods to keep this data safe and secure while transmitted over your home network and through the Internet to our servers.

I'd say the text is somewhat ambiguous on *where* this stuff is being stored. Given that it's all "password protected", that would tend to imply they're talking about the server side, since there are no passwords in the thermostat.

As to the proximity sensor, I've discovered mine works, but only if I wave my hand a few inches in front of it. At 12 inches or more, it never wakes up.

As to the charging and network unavailability, I've noticed a pattern that they're unavailable at night and available during the day. I hope that the learning process can figure out that I'm more likely to want to dork with my thermostats at night, after my kid's in bed.