There are a few people who are VERY conscientious about keeping their creations clean and free of CC and don't use them themselves in their own games. Some I trust are follyfoot, LariFari2009, who does amazing recolors to the point they don't look like standard EA patterns, and our own Agneza. Even there though they could inadvertently pick up a "sleeper" cc without knowing they have it. I have totally given up on downloading patterns from the Exchange as they often have caused problems and I only download builds or characters from the above mentioned few. I love the really gorgeous and fanciful Sims that some create but it is so obvious they have used CC hair or such I just don't take the chance.