Basically (as has been pointed out below), authentication is more of an issue in the opposite direction - when the GSM spec was hammered out, carriers were concerned with rogue handsets, not that someone, somewhere would set up a rogue network (as the package in the article pretty much is, at least from the perspective of the established carriers.)<p>In NMT networks, for instance, ghost handsets were a major issue - you could register onto the network and place calls and the operator would have nowhere to send the bill.<p>Not such a good idea for ordering pizza, but great for lengthy international calls.<p>Here in Norway I seem to recall that our national telco simply blocked calls from the NMT cellular network to a number of countries on the assumption that any call placed would be fraudulent, anyway.