Just a thought, but wouldn't CDMA in theory be more secure due to the central authentication structure vs gsm with sim cards that one could spoof/copy?
CDMA is also spoofable. People illegally spoof CDMA modems for free internet access all the time.
it's also possible to set up a cellular base station and trick people into connecting to it.
http://www.wired.com/threatlevel/2010/07/intercepting-cell-phone-calls/
That's an article on it being done with GSM, but with the advent of software defined radios and GNU radio, I don't see why it couldn't be done on any of the 3g technologies (HSPA, CDMA) too.
Cloning an ESN or SIM card to steal internet access is one thing. Reading user data as it goes over the air is another thing altogether, and as far as I know, it's not easy.
Of course it's not impossible, but anyone setting that kind of thing in the corner of the coffee shop will look pretty suspicious. The guy sitting in the corner with a WiFi netbook probably looks pretty normal.
I don't know how much this is either fact or fiction, but allegedly US spy agencies like the FBI have portable cellular antennas. So if they want to do a bit of cellular wiretapping on someone, they set up shop in the general vicinity of the target. The person's phone then latches onto this portable antenna as it provides a much better signal, and they can trap all signals going in and out of that antenna.
Quite safe. The only real entities that could afford the necessary equipment and personnel to do this easily could just ask the phone company for your records or legally have the data recorded at the other end, so unless they're using it for intelligence purposes, they won't bother doing it. It's way more likely for your phone to become compromised and start handing out information it shouldn't be to other parties than it is for them to perform some kind of man-in-the-middle attack on a cellular network.