Worth mentioning that unlike some ISPS Xfinity does let you use your own DOCSIS modems, which is the ideal way of using an ISP. ISP provided gateway's WIFI is not ideal for privacy, security and performance.

Comcast in general has a long history of snooping around and messing with users' traffic. Not that the alternatives are much better. Regular folks are screwed on this matter.

But perhaps for HNers setting up your own trusted WIFI AP and routing it (and all other traffic) through an internet gateway that routes your traffic over a secure channel (whatever that is for you, Tor, VPN services, VPN over your own cloud/vps,etc..) is ideal. It goes without saying, your DNS traffic should also not be visible to the ISPs.

Keep in mind that they sell all this data (including the motion data) not just to law enforcement but to arbitrary well-paying data brokers and other clients.