What if you occasionally like some of the more unusual things, off the top of my head "women with goats" I think we can agree you don't want even your most open minded best friend finding this. So you make a more obvious easier to find folder with more acceptable videos as a decoy.
I wouldn't mind. If they snoop around my PC and are shocked by what they find (although I highly doubt that they would) then they should deal with it.
If your friends are very religious or something I can understand why you'd want to spend extra effort to hide stuff. But even then if they don't want to know they shouldn't be opening a folder called "porn".
