I'm sure people will want to make it seem like Comcast is doing something evil here, but they're not:

> Comcast does not monitor the motion and/or notifications generated by the service.

> This feature is currently only available for select Xfinity Internet customers as part of an early access preview.

> WiFi Motion is off by default.

Features like this at Comcast are typically one or two engineers on a random team coming up with a cool idea, testing it out, and if it works, they ask if they can roll it out en-masse. If it's just a software or server/backend thing and it doesn't have any negative impact, it gets accepted. Despite their terrible customer service and business practices, they do some cool stuff sometimes. They also release a fair bit of home-grown stuff as open source, which is expensive and time-consuming, but [they hope] it attracts engineers.