I am not aware of any CP distribution taking place over PIR, although OFFsystem might qualify for that, I know little about OFFsystem though. I am not saying this is how CP distribution today is done, but I am saying that if your primary issue with CP viewers is that the demand they create leads to production, then that issue would be solved if distribution took place over a PIR system. If the possibility of determining popularity of material by uploading to non PIR distribution mechanisms exists, then that would only apply to people who are actually uploading content. So still, your major gripe with CP is addressed in a world where all CP transfers are done via PIR. And you are left only being able to use your 'demand leads to more production, so should be banned' argument against people who upload or download outside of the PIR.