This definitely bothers me. In fact, it makes me angry. I use an iPhone, which is generally very good about allowing me to control how my location data is used. I'm super careful about which apps I give location access to. But it turns out none of that matters because T-Mobile is selling my location data to whoever wants it and there's no way for me to control that.
It should be illegal for companies to sell location data like this. I'm so glad my senator, Ron Wyden, is fighting for laws that will prevent this kind of thing.