The article does say that they pin pointed the potential culprits to a few seats, followed through, waited for the culprit to repeat their act and then catch hi

The article does say that they pin pointed the potential culprits to a few seats, followed through, waited for the culprit to repeat their act and then catch him red-cameraed. The method worked. Of course, it worked well most likely because the angle was extreme enough to narrow it down to a small set of seats. But it is also true that cammers would not dare to record it from a well vantaged location for the fear of being called out.