Clarification about "Clean Audio Folder"

I am uncertain about the checkbox "-recurse" with this statement next to it: (all wav files below this point belong belong to Sonar HS Projects). So what would be the point of checking that box?? - If I do not check that box, then at this point NO files are found to be deleted when I do a search. I kind of find it hard to believe that there are none.  If this box is not checked, will files to be deleted appear there?  I have seen that if I do check it, many files will appear in the box.