§ 64.2007 (b): Except for use and disclosure of CPNI that is permitted without customer approval under § 64.2005, or that is described in this paragraph, or as otherwise provided in section 222 of the Communications Act of 1934, as amended, a telecommunications carrier may only use, disclose, or permit access to its customer's individually identifiable CPNI subject to opt-in approval.
§ 64.2005 (a): Any telecommunications carrier may use, disclose, or permit access to CPNI for the purpose of providing or marketing service offerings among the categories of service (i.e., local, interexchange, and CMRS) to which the customer already subscribes from the same carrier, without customer approval.
Today's email: Fi may wish to provide you with additional information about products, services, and offers from our Alphabet affiliates, including Google LLC, that aren’t among the category of services you’re already purchasing from us
Google plans to advertise outside of the user's existing service category. § 64.2005 says that with opt-out consent, they can only do this within the existing service category. Since it doesn't fall under a § 64.2005 exemption, § 64.2007 (b) says that this requires opt-in approval.