A conversation between a passenger and an airline has gone viral, largely because people find it intensely creepy.

MacKenzie Fegan went to the airport last week. As with normal flights, she was expecting at some point to present her boarding card in order to get on her plane. However, she found all she had to do was look at a camera, and at no point was asked for her pass.

As convenient as that sounds, she had questions, which she put to the airline, JetBlue, in a now-viral thread.

-

-

Fegan had several pressing follow-up questions, such as "how" and "who exactly has my face on record?".

"Presumably these facial recognition scanners are matching my image to something in order to verify my identity," she wrote. "How does JetBlue know what I look like?"

-

-

-

-

-

-

So how concerned should we be that companies like JetBlue have access to this data?

"You should be concerned," the Electronic Frontier Foundation wrote on Twitter. "It’s unprecedented for the government to collect and share this kind of data, with this level of detail, with this many agencies and private partners. We need proper oversight and regulation to ensure our privacy is protected."

This has been happening for a while behind the scenes, and is likely to become more common. Delta opened the first facial-recognition-powered terminal last year in Atlanta. The Department of Homeland Security in a report last week said that it wants to roll out facial recognition technology to be used on 97 percent of departing airport passengers by 2023.

It's convenient and fairly sci-fi, but it appears a lot of passengers find it quite creepy, particularly because of privacy concerns.

-

-

-

The system called (in somewhat sinister language) "Biometric Exit" cross-references a photo of your face taken when you look into the camera with images from a Customs and Border Protection (CBP) database containing photos of you from passport and visa applications, The Hill reports.

“Once you take that high-quality photograph, why not run it against the FBI database? Why not run it against state databases of people with outstanding warrants?" Professor Alvaro Bedoya, founding director of the Center on Privacy & Technology at Georgetown Law, told The Verge.

"Suddenly you’re moving from this world in which you’re just verifying identity to another world where the act of flying is cause for a law enforcement search.”

As it stands CBP retains any images in its database that are flagged for inspection (e.g. because someone has outstayed their visa or failed to obtain a visa in the first place). That's a lot of data that departments like the FBI might like to get their hands on, and there's only going to be more of it as the system is rolled out over the next four years.