It doesn't require a WiFi device to work.

> If you’d like to prevent your pet’s movement from causing motion notifications, you can exclude pet motion in your WiFi Motion settings by turning on the Exclude Small Pets feature. > Motion is detected based on the amount of signal disruption taking place between the Xfinity Gateway and your selected WiFi-connected devices, so motion from small pets (around 40 pounds or less) can be filtered out while keeping you notified of large movements more likely to be caused by humans.

It's basically passive radar using the wifi bands as the reflection AFAIK. It doesn't seem to be about the active state of devices, but the deflections in known points. It's creepy.

A much easier alternative is to not enable the feature on your router.

It's an opt-in feature. If you don't set it up, they aren't generating the home/away chart like shown in the article.

I was thinking of attaching a wifi enabled device to a roomba if you wanted to appear to be home when you weren't. I would hope, though, that doing something like this wouldn't be illegal. It's your home, your stuff, etc. Besides, I don't want to get arrested for leaving a rotating fan on or something.

This technology doesn't rely on you actually having a WiFi device on you. It can detect presence/motion by changes to the standing waves of the EM propagation throughout the room.

As the salty water meatbags move from room to room we change how the reflections and scattering patterns of 2.4 and 5GHz waves move. Studying these changes and some calibration, you can even determine small changes (like is the person on the left side of the room breathing, are they standing or prone, etc).

In their docs, they show using the WiFi connection from a printer to determine motion sensing and have the option to exclude pets.