Your police department runs license plate reader cameras that photograph every car driving past. Not just the speeders, and not just the suspects. Your car, several times a day, on the way to work and back again.

Police call these systems license plate readers, or ALPRs for short. If your city bought them from Flock Safety, you may know them as Flock cameras. Whatever name sits on the invoice, somewhere your agency wrote a policy governing how those cameras get used. That policy answers four questions. It says who may run a search and what reason they have to give first. It also says how often a supervisor reviews the logs, and which outside agencies can reach into your city's cameras.

In most states that policy is a public record. So is the paperwork it should have generated along the way.

So get the rule they wrote for themselves, then ask for the records that rule should have produced. That is the whole method, and the useful part is that it never asks you to win an argument about the Constitution.

Why is it called Must Exist?

Every request in this method opens with the same sentence, and that sentence is where the name comes from. If this decision was made the way the policy says it was made, then the following records must exist.

You are not guessing at what an agency might be sitting on. You are reading the rule the agency wrote for itself. Then you work out what paperwork that rule generates whenever somebody follows it, and you ask for that paperwork by name.

There is an honest limit here, and it is worth saying plainly before an agency says it for you. A record does not become required just because a requester would find it useful. The strength of a Must Exist request comes from anchoring it to a written rule, a contract term, or a statute that creates the obligation. If you cannot point at the rule that generates the record, you do not have a request yet. You have a hunch, and the custodian will say so in the reply.

Accept that limit and it starts working for you, because a request built on a rule the agency adopted cannot be brushed off as a fishing expedition.

What three license plate reader records should you request?

Three documents do most of the work, and there is a request template for each one. Ask for them in this order.

1. The use policy. This is the general order, the SOP, or whatever written directive governs camera use. It comes first because every other document you ask for gets measured against it.
2. The query audit log. This shows who ran a search, when they ran it, from which account and which agency, and what reason they typed in to justify it. Ask for it in its native electronic form, with personal identifying information removed.
3. The sharing roster. This lists the outside agencies and networks your city's system is configured to share with. It is the least requested document in the whole field and often the most revealing. It tells you who else has been reaching into your cameras, and it tells you which neighboring agency to ask when your own goes quiet on you.

Once all three land on your desk, set them side by side. Compare what the policy promises against what the logs actually show, then against who actually had access. Nearly every useful finding in this field lives somewhere in the gaps between those three documents.

What happens after you file?

There are three ways this goes, and every one of them leaves you holding a document you did not have before.

1. The paperwork matches the policy. The agency runs a real process and can show its work, which happens more often than the internet lets on. Say so publicly, and say the agency's name while you do it. Praise costs you nothing, and it is why the next custodian down the road bothers to answer you at all.
2. The paperwork does not match the policy. When a policy promises quarterly supervisor reviews and the agency cannot produce a single one, you are not offering a theory about surveillance. You are measuring the agency against a standard it wrote down and adopted for itself. That is a much harder thing for anyone to argue with.
3. The agency certifies that no responsive records exist. The certification is itself a document. You can publish it next to the search volume and the policy language promising those searches would be reviewed. It is not proof of misconduct, and this page will not pretend otherwise. What it is, is a written statement a council member can read out loud at a public meeting.

Filing guarantees you a written record, and nothing past that. Not an outcome, and not a change in policy.

What about warrants?

You will see this framed everywhere as a single gotcha question: how many of those searches had a warrant behind them? Be careful with that one, because it will cost you credibility faster than anything else on this page.

No court has held that a routine plate camera query requires a warrant. So say an agency tells you it does not require a judge's approval for standard searches. It has just handed you a lawful disclosure of its own policy. That is not a confession of wrongdoing. Treating it as one is exactly how a records project gets laughed out of a council meeting, and when that happens the project usually deserves it.

The version of the question that actually works is narrower. Look for a place where the agency has bound itself. Its own policy, its contract with the vendor, or a state statute may say that some category of search needs a judge's approval or a supervisor's sign-off. Then ask for the records proving it happened. Now you are measuring the agency against a standard it already accepted, and whichever way the answer comes back, it means something.

Does this ask for anyone's plate number?

No, and we say so inside the request itself, in writing, before the agency gets a chance to raise it. We do not ask for plate numbers, vehicle photographs, owner records, investigative targets, or informants.

Read your own state's exemption closely, because it is almost always broader than people assume. Florida's section 316.0777(3) is the one I know best. It makes confidential both the images themselves and any data containing or providing personal identifying information. It also covers that same information when it comes from those images. So this is not a narrow rule about one column labeled plate number. It reaches free-text fields, linked identifiers, and anything else that would let a reader reconstruct who a search was about.

The method aims instead at everything those statutes are written around. That means the contract, the purchase order, the use policy, how the sharing is set up, and the process facts inside an audit record. Whether a given field survives the exemption depends on what is actually in it. The agency carries the burden of naming the exemption it claims and handing over the rest.

What did the Supreme Court decide in Chatrie?

On June 29, 2026, the Supreme Court decided Chatrie v. United States, No. 25-112. The vote was six to three, and Justice Kagan wrote the opinion. The Court held that police conduct a Fourth Amendment search when they obtain a person's stored cell phone location history. The reason is that you keep a reasonable expectation of privacy in the record of your own movements, even when a company is the one holding it. The Court then vacated the decision below and sent the case back, leaving the validity of the warrant for the lower courts to sort out. It also held that pulling just a limited window out of that database is still a search.

Does Chatrie make license plate readers illegal?

No, and anyone telling you otherwise is running well ahead of the law. Chatrie was a cell phone location case that never mentioned plate cameras once. No court has held that a routine plate reader query counts as a search requiring a warrant.

The case pointing the other direction is real and recent. In Schmidt v. City of Norfolk, a federal judge in Virginia upheld the city's camera network. Chief Judge Mark Davis ruled on January 27, 2026 that it was not an unconstitutional search. The city ran not quite two hundred cameras and held the data about three weeks at a time. His reasoning was that a network that size does not yet paint a full enough picture of any one person's life. In the same opinion, he warned that a bigger one someday might. The plaintiffs, represented by the Institute for Justice, have appealed to the Fourth Circuit as No. 26-1227, with the Cato Institute backing them.

The law here is unsettled and still moving, which means anybody selling you certainty about it is selling you something.

And that is exactly why this method does not lean on any of it. A public records request asks a much simpler question: did the agency follow the rule it wrote down for itself? The question has an answer today, in every state in the country, no matter what the Fourth Circuit eventually decides.

Why file now instead of waiting?

In November 2025, a Washington judge ruled that plate camera data are public records under that state's Public Records Act. Cities across Washington responded by switching their cameras off rather than comply. Then, on March 30, 2026, Governor Bob Ferguson signed Senate Bill 6002, which among other things exempted that same data from public disclosure.

A court said the records were public, and the legislature turned around and said they were not.

Understand that endgame before you start rather than after. When records law becomes inconvenient enough, the fight moves off the custodian's desk and into the statehouse. So file while your door is still open, and keep an eye on your own legislature while you do it. Lobbying over disclosure rules is a story in its own right, and lobbying filings happen to be public records too.

Has this actually worked anywhere?

Cities have been canceling their plate camera contracts since 2025, and in a growing number of those cases the sequence ran the same way. Residents pulled the query logs, the logs turned up searches run by agencies the city had never authorized, and the contract died at a public meeting a few weeks later.

The residents got the records first, and the politics followed the records. You will not be inventing that sequence from scratch.

Where do I get a public records request template?

Right here, and you should not be writing one from scratch.

A Must Exist request is really a template with three blanks in it. The agency you are writing to, the rule you are anchoring to, and the records that rule should have produced. Fill in those three and you have something ready to file. Everything around them stays roughly the same from one agency to the next, because the mechanics of a public records request do not change much across state lines even when the statute numbers do.

That is why the template is written to work in any state. Wherever a citation belongs, it sits in brackets on the page until you look up your own state's number and drop it in. Nothing goes out the door with a number somebody guessed at, because an unverified number is still visibly a blank.

If you have used a FOIA request template before, this will feel familiar with one difference that matters. A generic template asks an agency for a topic. A Must Exist template asks for a specific document the agency's own rule already required it to create, which is a much harder thing for a custodian to wave off. The plate reader version is that same skeleton pointed at three targets: the use policy, the query audit log, and the sharing roster.

How to file your first public records request

The method and its request templates are free, published under a Creative Commons Attribution license, and attribution is the only string attached.

• Must Exist Campaign — run the campaign with me →
• Must Exist Autopsy — a live class in records practice, not law →
• Read the case files on Substack →

Stop tweeting at the surveillance state. Start filing against it.

I am not a lawyer, and nothing on this page is legal advice. What you will find here is process guidance and template language. Records law varies a great deal from one state to the next and from one set of facts to the next. If your situation turns on your own circumstances, talk to a lawyer licensed in your state.