Leave Your Cellphone At Home, Says Jacob Appelbaum
An anonymous reader writes "N+1 has an interview with Jacob Appelbaum (who is part of the Tor project) titled 'Leave Your Cellphone at Home.'" Jacob has a lot to say about privacy, data security, and surveillance. He ought to know. Among other things, he's had his email seized, been relieved of his phone, been the subject of a National Security Letter (video) and generally had his travel disrupted.
You could just leave the SIM card at home and take the phone with you. The wi-fi capability is all you need to maintain communications with the outside world in most urban environments, and doing encrypted, TORed VOIP over a wifi connection shouldn't identify you like the SIM would.