I like this idea also, but yes it would be near impossible to implement, even with a stupidly huge dev team and Zuckerberg's credit card. The only way I can see this happening is if the public was allowed to develop add-ons, models and textures for it them selfs, but even that would be a huge effort to manage. Every script would have to be checked, every model and textured copyright assured. The possible problems are endless and way beyond a human to predict. That said, if this does ever happen, i don't want any police as such, policing should be a done every friday night by the public, armed with pitch forks and a list of wrong-doers.