I've already composed my reply in case I receive one of these letters someday. "Dear Comcast, I am so sorry. I had no idea that copyrighted works were being downloaded via my IP address; I have a wireless router at home and it's possible that someone may have been using my connection at the time. I will do my best to secure this notoriously vulnerable technology, but I can make no guarantee that hackers will not exploit my network in the future." [salon]
Sort of an interesting turn -- trusting your neighborhood freeloaders more than your ISP.
