I don't know of any cases on digital fingerprinting that have gone to court. There are several cases against MySpace (Rupert Murdoch's News Corporation) and YouTube (Google) for copyright infringements, however - for instance, Viacom is suing Google for over $1 Billion for copyright infringement - which is one of the reasons fingerprinting software has been worked on so diligently the last 5 years.
Google hopes to have technology in place by next month to filter out content that may infringe copyright. The task, however, is an enormous one, with many complications. The music and videos must be converted to digital files - basically a series of ones and zeros - and digital fingerprinting records these series, using pattern matches to filter out the infringing material. Music and video producers submit their original copies to Google and Google converts the originals. In tests, the filters don't work well, however, so music and video producers would still have to monitor the sites. Other tech start-ups are working on watermarking and hiding copyright and authentication data in the videos and music.
Those familiar with computer technology have not had problems changing file names, snipping videos into short clips to avoid pattern matching, adding characters and sounds and other video, or stretching or waving video to confuse the system. Algorithmic filters can be subverted using all sorts of techniques. Plus, no filter can yet determine what is fair use, so this is a problem to be overcome, as well.
With infringers facing billion dollar suits, however, there is definitely the incentive for companies like Google to develop a system that works well.