This came up a while ago in a thread, can't remember why. Basically, this is what I remember.
The perfume industry tried to instate some standards of copy rights. They then conducted a study to find out the impostors and help the original nose get credit or something. They found that some of the classics were copies of lesser known but extremely similar perfumes. So, they threw that out.
Think of it like this. Rose (as a note) = Rock.
How many bands play rock that is extremely similar, but just barely different? Is Chuck Berry going to sue because he has the first documented hit of a rock song? He could, but he wouldn't win, because the copies are just different enough. There are numerous differences between Mabelline and Crazy Bitch, but at first listen, they're both rock, and the names are similar (Chuck Berry, Buck Cherry). It's really too complex an issue to say CW is a clone of GIT when GIT was a copy of something else.