These smuggled cell phones have turned out to be an intelligence bonanza, although not everyone has taken advantage of it. In Moslem nations, where hundreds of Islamic terrorists have been imprisoned, the local culture of corruption often gets cell phones into the hands of the prisoners. While most of the calls are to family, some are going to terror associates. Some nations have been more cooperative than others in allowing U.S. intel agencies to tap into these terrorist communications. This may be for the same reason that some countries restrict American interrogations of captured Islamic terrorists. It is believed this is because the local police have had dealings with some of the terrorists, things they would rather not share with their American "allies." The locals seem more willing to install cell phone jammers in the prison (which, of course, can be turned off for a while if you pay the right guard the right amount of money).
The recent prison uprising in Brazil, accompanied by gang organized attacks on police outside the prisons, was all made possible by the large number of cell phones that had been smuggled into prisons. As long as there have been prisons, there have been guards who could be bribed to bring in contraband. While most guards draw the line at bringing in weapons, few of those engaged in smuggling feel any qualms about slipping in drugs, porn, food delicacies or cell phones.