Hidden camera in the stadium: A concert agency has apparently secretly filmed fans of Taylor Swift and a software to analyze the faces. Accordingly, videos of concert rehearsals were shown on a screen at a kiosk. A hidden camera behind the screen filmed the faces of all the visitors who watched these videos.

This is the result of a report by the music magazine "Rolling Stone". The author refers to the security chief of the event agency Oak View Group. The agency's staff had been on-site to test the software. SPIEGEL ONLINE has asked the agency and the management of the artist, an answer is still pending.

According to the report, the images of the fans have been sent to a server in Nashville, where they were compared with the entries in a database. There, the facial features of the visitors have been compared to photos of hundreds of people known as stalkers of the singer. The artist has struggled in the past several times with massive stalking attacks.

Tech companies worry about user privacy

Basically, facial recognition is a delicate measure to identify visitors. Finally, the data must be saved for comparison - which is already explosive, because many users use their face as a password and unlock their smartphones for example. If the data gets into the wrong hands, users can hardly do anything about it and have to give up their face as a password.

The problem: In the US, there are few privacy rules for face recognition. This is especially true for concerts that leave the house right as a private event the organizer. As a result, even big tech companies that make money with face recognition are worrying about user privacy. Microsoft called last week to finally take political action to regulate facial recognition.

Otherwise, the large-scale use of technology is hard to stop. For example, the US ticket provider Ticketmaster announced in May that it would use the Blink Identity software to speed fans through turnstiles at the entrance (PDF). In fractions of a second, the system detects the faces and determines if the fan has a valid ticket.

In Germany such an action could be expensive for the organizer: since May this year, the basic data protection regulation applies in Europe. Anyone who secretly films a concert violates the rules. For example, if you want to film people and scan sensitive data such as faces, you must clearly indicate this on the ticket and how long the information will be stored.