Assuming the copyright police are doing their job correctly, there must be evidence of your wrongdoing and they will have a copy of it. But don't they already own the copyright? And if so, is sharing the file - allegedly - still a copyright offense? And if so, isn't anybody who bought the DVD likewise liable for copyright infringement? Let's assume they have the copy you are alleged to have shared. In court you have a right to full disclosure which includes a copy of all the evidence against you, and therefore the Cubo file itself, so you should ask for that up front. If they don't have or are unwilling to provide it you can assume they have no case and are fishing for victims, and that might itself be a crime in your state. If they hand over the goods then grab some popcorn and check it out. You win either way.