In Europe, one of these preventative measures, a robots.txt file, 328 was put
into question in Copiepresse’s infringement case against Google.329 Google
argued that “newspapers had explicitly or implicitly consented to [Google
News’] use of their materials by not using standard technical means . . . to stop
their publications being indexed by search engines.”330 The Court of Appeal of
Brussels rejected this argument on the ground that copyright is a right to prior
authorization, not a right to opt out of a particular use.331 While the argument
of an implied license failed in Europe, the United States has found implied
licenses to exist in the context of search engines storing copyrighted work