Imagine a world where all your credit cards, local, state, and national IDs, library and customer advantage cards are obsolete. Fraud is impossible: crimes are solved within minutes. Utopia, one might think. Utopia, as long as privacy and anonymity lose their value. Utopia, except for those who dissent from the established order. Utopia, as long as the powers that exist remain benevolent. Freedom is slavery, and ignorance is strength.

Welcome to the future of Leon, the sixth-largest city in Mexico. In collaboration with Global Rainmakers Inc., a U.S. biometrics firm, Leon is implementing a city-wide system of iris scanners. These devices will be able to track individuals throughout the city — in public transit, in retail stores, in corporate offices. Advocates claim the scanners will help law enforcement and make life easier for citizens. And yet this argument, as it so often does, fails to correctly balance the advantages of security with the costs to privacy.

While the introduction of a comprehensive iris scanning system in a large U.S. city would attract tremendous media attention, the system in Leon has gone nearly unnoticed in the mainstream media. FastCompany magazine has had the most in-depth coverage, and of the major news outlets, only USA Today has featured the iris scanning technology. Even with this limited coverage, the intentions of Global Rainmakers seem ominous. FastCompany quoted Jeff Carter, CDO of Global Rainmakers, as saying that “every person, place, and thing on this planet will be connected [to the iris system] within the next 10 years.”

The entire iris scanning system is, at least for now, opt-in for everybody except criminals. In theory, individuals could choose to keep their antiquated identification cards. But even though authorities may not be forcing people to register their iris patterns, Carter’s theory of an opt-in system involves little choice. As quoted in FastCompany, Carter believes that “when you get masses of people opting in, opting out does not help. Opting out actually puts more of a flag on you than just being part of the system. We believe everyone will opt in.”

It seems likely the iris scanner system will be implemented in Leon without much opposition. And, if the experiment in Mexico goes well for the government, American cities may be next. With closed-circuit cameras in London, warrantless wiretapping, and airport security scanners, iris scanners hardly seem like a large step. But pervasive tracking is a danger to freedom and to privacy. It gives authorities the power to crush dissent before it can gain strength. The system may disrupt fraud, but it will also disrupt liberty.

Michael Kahn is Forum editor for The Tartan at Carnegie Mellon University.