As the target of numerous death and rape threats, Swift arguably has a valid motivation for leveraging such technology. However, it's unclear who has ownership of the photos of her concertgoers, or how long they will remain on file. Her representatives have also not yet responded to queries as to whether fans knew about the cameras.

Facial recognition technology has attracted numerous headlines in 2018. The American Civil Liberties Union (ACLU) recently announced the Secret Service plans to use the tech in and around the White House, but that it was unclear how the images would be classified. Meanwhile, Amazon has been selling its facial recognition software to law enforcement agencies, with the ACLU revealing in July that it had mistakenly matched 28 Congressman with the profiles of known criminals.

Despite privacy and consent concerns, however, facial recognition technology is tipped to play an increasingly large role in everyday life -- and that includes events such as concerts. Earlier this year, Ticketmaster invested in a startup called Blink Identity which builds sensors that can allegedly identify people walking past at full speed in less than a second. The ticketing company says it hopes to eventually use the tech to get people through turnstiles faster, but again, it's not clear how that data will be used in the long term. So until these concerns are addressed across the board, people will rightfully be wary of facial recognition technology, regardless of where they are.