While you might be used to the sight of Customs and Border Protection agents checking the passports of travelers arriving in the United States from abroad, passengers on a recent domestic Delta Air Lines flight had the unusual experience of having to show identification before they could leave the plane.

Anne Garrett, a video editor for VICE News, was on the flight from San Francisco to New York City. She says that shortly after the plane landed at John F. Kennedy airport on Wednesday night, flight crew announced that passengers would have to show their “documents” to CBP officers upon exiting the aircraft.

Passengers were confused, she says, as to what “documents” actually meant, until a crew member said it meant showing a passport or other form of government-issued identification.

According to Garrett’s account, two CBP agents were waiting on the jet bridge to check IDs.

“I said, ‘Why do you need to see this?’ He just took it out of my hand,” Garrett said. “It’s a tough situation to be in because everybody wants to get off the flight. You don’t want to be the one holding up the line.”

CBP confirmed the incident in a statement to VICE, saying the agents were there because Immigration and Customs Enforcement (ICE) had asked for help finding an individual “ordered removed by an immigration judge.”

“To assist our law enforcement partners, two CBP officers requested identification from those on the flight in order to help identify the individual,” the CBP statement said. “The individual was determined not to be on the flight.”

Delta told VICE it contacted CBP “to get a sense of why their presence was needed,” but didn’t offer any other comment.

Although Transportation Security Administration agents ask for travelers’ ID before they’re cleared at airport security checkpoints, VICE points out that no one is legally obligated to comply. Or sometimes, you might not be able to, like if you lose your license and passport and all you have is your school ID or a credit card with your photo on it. However, you will probably be taken aside for additional security screening by TSA agents to make sure you are who you say you are, per the agency’s policy.

Hugh Handeyside, a staff attorney for the ACLU’s National Security Project told VICE that CBP should have to explain why officers demanded IDs on a domestic flight.

“CBP is not an always-and-everywhere police force, and any attempt to expand its operations beyond its authority would raise serious concerns,” he said.

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