This action is considered legal in the US.

Singer Taylor Swift held a concert at the Rose Bowl, California last May. People attending this concert are tracked by an advanced facial recognition system. The target of this system is stalkers, bad guys who specialize in following and bothering Taylor Swift.

The identification system is equipped at kiosks, where highlight videos of Swift during rehearsals are shown. Anyone who visits the kiosk will have their face scanned. After that, the data will be transferred to the center in Nashville, Tennessee to compare with photo data of stalkers that Swift knows.

Until now, American artists have not publicly announced the use of facial recognition technology at their concerts. However, under US law this practice is legal because the concert is technically a private event where the organizers can subject attendees to any surveillance.

The protection Swift uses may seem a bit extreme, but this isn’t the first time facial recognition technology has been used to detect bad guys.

Last April, Chinese police arrested a 31-year-old suspect among 60,000 people attending a concert at the Nanchang International Sports Center. The suspect was discovered by Sharp Eyes’ identification system when he went to the concert even though he was wanted.

In the US, facial recognition technology is still being researched and applied to other fields. Ticketmaster is aiming to replace movie tickets with customers’ faces.