People think they have a right to give a copy away as long as it is for "personal" use. It is a perversion of copyright law that has been passed around the Internet and misunderstood as to its application. It was never meant to be applied to 3D models. I realize people may do these things once out of innocence...but when they do it over and over again, then they are doing it because they can, not because it is the right thing to do.