> The customer has to opt-in to WiFi motion sensing to have the data tracked.

  - Is this true if Law Enforcement gets a subpoena? 
  - Is this true if Law Enforcement asks "nicely"?
  - Can Xfinity activate it without the user knowing?
    - Does it explicitly notify the user when the setting has been changed? (e.g. done by LE, hacker, or an abusive partner)
  - Is this a promise and a promise that by default it will stay off?
  - Is the code to perform this feature pre-installed and able to be trivially (or even non-trivially) activated by hackers? 

Idk, there's a lot of questionable things here and Xfinity doesn't have the best track record that gives me a lot of confidence that we should trust them. This seems like an easily abused system that can do a lot of harm while provides very little utility to the vast majority of people.