Ignore the Cops

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For the past few months, police departments have been using a new iris scanning device to identify people they encounter. Many more police departments will begin using this device soon. The scanner can be held up to the eye of any person and almost instantly identify them more accurately than a fingerprint. Police have imposed restrictions on themselves to prevent misuse of iris scanners. Like a chubby kid guarding a Happy Meal, indulgence is more likely than restraint.

Currently, iris scanners are limited to checking the person scanned against a national database of iris scans. This database presumably only contains criminals, children and individuals who may need assistance, like alzheimers patients. The devices are not supposed to be able to capture and store new entries. These self-imposed limitations may only be temporary.

Warrantless Iris Scans Are Probably Unconstitutional

Although not yet tested, there are some potentially strong constitutional challenges to many iris scans that are likely to occur. If you have a reasonable expectation of privacy in some information or item, the police need a warrant to conduct a search. (Katz v. United States) There is no reasonable expectation of privacy for things that are in the plain view of the public. (Texas v. Brown) Technologies that enhance the senses to be able to see what is in plain view, like common binoculars, can be used by police without a warrant. (Dow Chemical v. United States) Something that is not visible to the naked eye is not in plain view. (California v. Ciraolo; Kyllo v. United States; People v. Arno) Police may also conduct a search that would otherwise require a warrant if they get consent. (Schneckloth v. Bustamonte).

An image of your iris and the detail of your iris is apparently very important information. Many people might reasonably expect to have a right to privacy in that intimate part of their body. Although the iris is held out to the public, the very intimate details, so much detail that the iris becomes a unique identifier, is not held out to the public because nobody can see that with the naked eye. A very powerful technology that can see more than the naked eye, even upon very close inspection, is required. Thus, such a search will likely be unconstitutional without a warrant.

Do Not Consent To An Iris Scan

If you agree to have your iris scanned for identification purposes, you give up any chance you had of fighting the constitutionality of a warrantless iris scan. Simply stating that you do not consent to having an iris scan taken should be sufficient.

Don’t Let Them Scan Your Face Either

These same devices are also capable of scanning faces for identification purposes. Preventing these scans is a bit more complicated because your face, and the ability to recognize you from your face, is most definitely held out to the public in plain view. To prevent face scanning requires knowing at what point in a police encounter the face scan is taking place. Knowing this will help you to know if you must submit or if you are free to leave.

Ignore The Police: “Free To Leave” Encounters

Police may stop people on the street in what is known as a “consensual” encounter for no reason at all. Police could potentially ask you for a face (or iris) scan during this “consensual” encounter. If you reasonably think you are free to leave you can ignore everything the police are saying and just walk away. (Florida v. Royer; Michigan v. Chesternut). If you aren’t sure, or you just want to be polite, one of the best things you can say is “am I free to leave or am I being detained?” Stopping the encounter as soon as possible before a scan of your face can be required is the best way to prevent a facial scan. If you aren’t free to go, you are being detained.


To detain you, the police need reasonable suspicion based on articulable facts that you are, have been, or will be committing a crime. (Terry v. Ohio) If a reasonable person thinks that they aren’t free to go, they are being detained. (United States v. Mendenhall). Here is where it gets a bit tricky. Some states permit you to remain silent to questions at this point, but many require you to at least provide your name. (Hiibel v. 6th Judicial District Court of Nevada) If you are in a no name state, you may be able to refuse a facial scan. This will probably make the police pretty mad so it might not be recommended. In states where your name is required, there is probably nothing you can do.


If the police then have probable cause to believe you committed a crime, they may arrest you. They will take you into the mug shot room where a long line of celebrities have taken their most memorable photos. At this point, there is nothing you can do to keep the police from putting your face in their facial recognition database.


Warrantless, unconsensual iris scans are probably unconstitutional. Face scans aren’t as inherently unconstitutional, but can still be prevented. If you are a law abiding citizen, these, and other tips from HowToVanish, can help you protect more of your privacy from one of the worst invasions of privacy that exist, police encounters.

Reprinted with permission from How to Vanish.

Bill Rounds, J.D. is a California attorney. He holds a degree in Accounting from the University of Utah and a law degree from California Western School of Law. He practices civil litigation, domestic and foreign business entity formation and transactions, criminal defense and privacy law. He is a strong advocate of personal and financial freedom and civil liberties.