Do we have an idea of how hard they're working to ID people? Did the people accused of pirating media do anything to hide themselves? Would a VPN have been enough to make it too difficult or annoying to track them down?

Edit, from TFA: "“This decrease results from a plurality of factors, such as the positive impact of the graduated response procedure, the transformation of practices regarding the consumption of cultural works on the internet, the acceleration of the dissemination of legal offers during the year, or even increasing use of workaround solutions (VPNs) by Internet users,” the regulator explains."