Here are some points to think over, Renderosity is a platform for people sharing 3d or poser interest we are talking here. People making free models motivates interest and more people to visit and also to buy stuffs. We should thank the staffs for their work rather than blame them. Rather than just a plain side of blaming others, why not think over some things like perhaps the models are too expensive, or why not release some low poly models for people to try. And the people in question are actually giving away as free rather than selling. They don't profit from it and are not redistributing the original models. The most if proven, then remove those models. No point blaming the staffs. If your item is good, people will buy them. Maybe out of the thousand download, some people already own the original stuff but just download for fun. Don't have to be so angry with such things, isn't it nice to know that so many people love your work?