Engadget is reporting that Comcast is introducing a new feature for its Xfinity xFi customers. Users will receive a push notification anytime there is a change in their network. If someone is using your WiFi when they are not supposed to this will alert you to that use, and if your username or password is changed you will also get an alert.
https://www.engadget.com/2018/03/02/xfinity-xfi-push-notifications/