This is what Google Analytics does, except with an app instead of an addon (that does not work).

Is there some legal requirement forcing them to offer an opt-out? And if so, how ridiculous and insecure can they make the opt-out? Anyone privacy conscious wouldn't install an app from someone as openly hostile as T-Mobile. What if one doesn't have the Play Store?

This is like a keyboard selling your typing data, and if you want to opt-out, you have to install a plugin for Google Docs...

And if they do, they will never get past the throbber.