I say you to it way. I sit in games long enough to recognize textures from CGTextures, GoodTextures, TotalTextures and others. Even if they are heavily customized. And that is even in AAA games, like Skyrim or Witcher 2 ;).
But I can assure you about one thing. Most people can’t spot a difference and more over most of them don’t care.
Besides taht most assets are customizable to some degree at least. If they are not, well they will loose with those that are.