Verizon is now doing this. If you opt out, they add new categories of tracking and then opt you back in:
> Custom Experience is a rebrand/spinoff of Verizon Selects, which customers were automatically enrolled into when they used the Verizon Up rewards program. Verizon Selects is being rebranded Custom Experience Plus (and anyone who was previously a member of Verizon Selects automatically gets moved to the new Plus program) and the standard Custom Experience program is being branched off of it, which allows the company to track many of its customers’ data use who do not actively opt-out.
Google's move feels similar. At least do a prompt of the user if you think they would want to opt in. Don't just opt them in automatically on your own.