Their case is based on two legal issues. First, that MediaSentry who reportedly gathered most of the evidence of alleged illegal file sharing, was not a licensed investigator in many of the states that it was working. Second, that "to prove copyright infringement, the RIAA needs evidence of that infringement, of course, but it also needs to prove it owns the copyrights in question. If it can't establish that fact, the case also falls apart," Camera told ars technica. "They basically committed a technicall screw-up". He claims that RIAA lawyers provided the court with copies of their copyright registrations, bu they weren't "certified copies" required under federal rules of evidence.
Do you think that the RIAA should be forced to return the fines it's collected?