Madison Square Garden has quietly been using facial recognition technology as a security measure to help identify who is entering the building, according to a new article in The New York Times. “MSG continues to test and explore the use of new technologies to ensure we’re employing the most effective security procedures to provide a safe and wonderful experience for our guests,” MSG said in a statement.  More:

It is unclear when the face-scanning system was installed. The people familiar with the Garden’s use of the technology, who were granted anonymity because they were not authorized to speak publicly about it, said they did not know how many events at the Garden in recent months have used it or how the data has been handled.

“In a lot of places we will see facial recognition framed positively as just an extension of video surveillance,” said Clare Garvie, an associate at the Center on Privacy and Technology at Georgetown Law Center. “But the reality is it is a way to require, or in secret, have everyone in a crowd show their papers, essentially, to compare them to a big enough database.”

The Garden — home to the N.B.A.’s Knicks and the N.H.L.’s Rangers, and hosts to events like boxing matches, concerts and the Grammy Awards — was already known for having tight security. There is always a heavy police presence in part because the arena is in the heart of Midtown Manhattan and is built above Pennsylvania Station, the nation’s busiest rail terminal. Fans attending events go through security screening that can include metal detectors, bag searches and explosive-sniffing dogs.

The Times also reports that this software in the private sector, with no access to goverment databases and watch lists, may have more advantages to venues in consumer marketing, where facial scans can approximate gender, race, and age and then then tailor ads for the demographic in attendance. It could also allow for less insidious things like ticketless entry and parking validation.

Other stadiums and arenas -- like American Airlines Center in Dallas and Golden 1 Center in Sacramento -- have experimented with facial recognition technology as well, though questions of privacy remain an issue. "I should know if I am being subject to facial recognition if I am going into any business, including a stadium,” Jay Stanley, a policy analyst at the American Civil Liberties Union, told The Times. “Even if you are just running my face against a list of people who have been banned from the premises and doing nothing else with it. I want to know. I have a right to know."