Cell Phones and Privacy

While governments in some countries have debated ending prepaid phone services because they enable criminals from avoiding law enforcement, I still think that they are necessary.  Many people use prepaid cell phones because they are cheaper than phones that have a plan, it is more convenient than having a plan (no commitment), minutes roll over, there are no hidden fees, you don't need any credit to get a prepaid phone, etc.  Prepaid cell phones should not be banned for these reasons.  However, I could understand if they were controlled by law somehow.  It would make sense to force users to register prepaid cell phones (to prevent criminals from avoiding the law), but it would only be fair to do that as long as people still had the freedoms I mentioned before that come along with using a prepaid cell phone.