Some people ask us, “What’s wrong with showing ID to police? If you are innocent and have nothing to hide, just show your ID, and you can be on your way.”

In the real world, however, showing ID can be a bad idea even if you are innocent. And the decision of the Supreme Court last week in Utah v. Strieff provides a case study in why you should never voluntarily identify yourself to police, and should avoid having any identification on your person if you don’t need it.

As we discussed when Utah v. Strieff  was argued in February, the sequence of events that led to this case was as follows: Police looking for drugs illegally stopped and detained a pedestrian without any articulable basis for suspecting him of any crime. While illegally detaining Mr. Strieff, the police asked (or demanded) that he identify himself, and he told the police his name.  The police ran a check on his name and found a record of a warrant for his arrest for a minor traffic violation.

Based on this warrant, the police re-classified the man already in their custody from “detainee” to “arrestee”, searched him “incident to his arrest”, and found — surprise — illegal drugs, which they had been hoping all along to find, but had lacked any legal basis to search for.

Strieff argued that he wouldn’t have been searched, but for the original stop and detention, which the police conceded was illegal, and therefore that the police shouldn’t be allowed to use the drugs they found as evidence against him. The Supreme Court upheld the legality of the arrest and search, despite the illegal stop and detention, and allowed the evidence to be used against Mr. Strieff.

Most of the commentary on the Supreme Court’s decision has focused on Justice Sotomayor’s dissent:

The Court today holds that the discovery of a warrant for an unpaid parking ticket will forgive a police officer’s violation of your Fourth Amendment rights. Do not be soothed by the opinion’s technical language: This case allows the police to stop you on the street, demand your identification, and check it for outstanding traffic warrants — even if you are doing nothing wrong. If the officer discovers a warrant for a fine you forgot to pay, courts will now excuse his illegal stop and will admit into evidence anything he happens to find by searching you after arresting you on the warrant….

We share Justice Sotomayor’s outrage. But what are the lessons we should take away from the majority opinion?

First, we can’t count on the police to tell us our rights. It’s not clear whether the police represented their “request” that Mr. Strieff identify himself as mandatory, or whether, while under police detention and not free to leave (and without having been read his Miranda rights), he knew that he had the right to remain silent and not give his name. But whatever happened, the Supreme Court majority doesn’t seem to have been much interested in these issues. Know your rights, and exercise them. By the time the police read you your rights, if they do so at all, it’s often too late.

Second, you should always exercise your right to remain silent when questioned by police — even if all they ask you is, “What’s your name?” Mr. Strieff’s detention would have remained illegal, and any evidence obtained by (illegally) searching him would have remained inadmissible, if he hadn’t told the police his name so that they could run a check for warrants.  This case shows that when police say, “Anything you say may be used against you,” that includes your name and any other identifying information you might disclose. Don’t tell police your name, and don’t voluntarily show them anything that might identity you. If you don’t need to have it with you, you are better off not having any ID on your person that might be found if you are searched on some other pretext.

Third, if you are tempted to think that you don’t need to worry because there isn’t a warrant out for arrest, think again. There are warrants out for millions of people in the US. Until they are busted, many people don’t know that there is a warrant for their arrest. Are you sure that every time you have ever gotten a traffic ticket, your check was received by the court and properly processed? If a bench warrant had already been issued by the time your payment was received and processed, was the warrant quashed? Was that fact reported to the FBI, and was the original record of the bench warrant removed from the NCIC database? Have you gotten your NCIC file recently to confirm this?  If not, there’s a non-trivial chance that there’s a warrant for your arrest, or that NCIC shows that there’s a warrant for your arrest. NCIC is riddled with errors, and the FBI has exempted it from the accuracy requirement of the Privacy Act. But the Supreme Court has said that an NCIC record of a warrant is enough to make an arrest legal, even if the data in NCIC is incorrect. You should always assume that NCIC might show a warrant for your arrest that any cop who runs a check on your name or ID will find. If you know this and still choose to identify yourself to police, you are practically asking to be arrested. If police stop or question you, they are looking for an excuse to arrest and/or search you. The only way — and the easy way, fortunately — to avoid giving police the basis to arrest and search you that they are looking for is not to tell them who you are and not to show them any ID.