A brief online review shows that the new Harry Potter movie can be downloaded and watched for free online. This damages the launch and undermines the exclusivity of the proposition.
Warner Bros say they are determined to catch the copyright thieves in this case but they could do with a little assistance from the ISP's to track the offenders down.
The ISP's current position (BT, TalkTalk, Virgin, Sky etc) is that they will resist providing assistance to content owners unless they have applied for an expensive Norwich Order. Further BT and TalkTalk have appplied for judicial review of the Digital Economy Act which was seeking to address this problem.
www.KLipcorp.com (as Iolo has pointed out) deals with issues such as this but the suggestion would be for the content owners to lobby the Department for Culture, Media and Sport to develop some backbone and stand up for the content owners against the ISP's.