 But the court disagreed with this argument because if this is the law, then "effective" copy protection measure will have to prevent against every possible current and future means of copying.Finally, RealNetworks asserted that regular DVD players can make temporary copies as cache, so ARccOS and RipGuard do not prevent copying.However, the court deemed this argument flawed by distinguishing that cache copies are byproduct of playback, but copies made by RealDVD are permanent.