Correct me if I'm wrong, but I don't think that a fully free cell phone OS is preventing you from being tracked. Even if free software was bug/backdoors free (I'm not sure about it). How do you connect to the network? Through a SIM-card, with an ID, linked to your cell-phone contract. And whatever goes on the broadband/network of your cell phone contract provider is free to read for him. You don't initiate your phone calls with an exchange of GPG keys with your contact, nor do you register your contract with a fake name. The only solution for that is the combination of a prepaid SIM in cash with encrypted VOIP on 3G+.
You can be tracked anywhere there's a communications infrastructure. It is required for things like law enforcement as well as being part of the protocols that run the network. Since basically every country on the planet does this, comparing it to a Stalinist order seems retarded, and I don't think it will ever change.
Better yet, if you are transmitting anything, there's these wonderful devices called "Radio direction finders".
We dont need to know how GSM is transmitted, or what encryption schemes they're using. If you are outputting a signal, you can be found. Hell, there's competitions for RDF.
Now, just not carrying a cell phone is a good idea on not being tracked. Next best is taking the battery out of the phone. "Off" does not mean off, even in airplane mode. Some GSM frames are still transmitted, as per what my fellow ham geeks have told me (I'm one as well).
