Prepaid cell phone privacy

Prepaid cell phones should still remain private in my opinion. The whole reason people get them is to not have bills, contracts, and remain anonymous. Also no one can find out their number unless the owner gives their number out. This is a major invasion of privacy if the government wants to track prepaid cell phones. That is their personal life and the government has no right to track them. Now depending on the company if they decide to have some sort of tracking system they may, although it should not be a requirement of all prepaid companies. Also some people use the phone a lot less than others, one prepaid can last an individual a long time. There are other means in catching criminals than cell phones and it is not fair to ban them because a small majority of people use them for harm.