"all of whom have solid track records of being hostile to privacy"
T-Mobile USA has to comply with CALEA (See: < https://secure.wikimedia.org/wikipedia/en/wiki/Communications_Assistance_for_Law_Enforcement_Act >) and with the FBI's DCS-6000, known as Digital Storm, and the other, classified, system, called DCS-5000 - which means they think you are a spy or a terrorist - can circumvent most any of the inconveniences that T-Mobile presents.
Triangulation techniques, using cell site reception parameters, have progressed to the point where location can be achieved measured in the single digit metres, unless obscuring RF technology is used.
A single FCC ruling could bring T-Mobile into the standard practice of other carriers. Sprint has gone even further when itestablished a website so that law enforcement agencies would no longer have to go through the trouble of seeking the assistance of Sprint employees in order to locate individual Sprint customers. This website was then used to ping Sprint users more than 8 million times in a single year. (Congressional evidence)