Don't know about anyone else, but I would not want a defrag program to decide which 'old files' to delete.
I making the assumption that a file that I have already deleted is flagged in the directory somehow as such. nor would I want a program that made it's own decision based on someone else's mind set of what to delete.
"somewhat inaccessible" I realize that files that have been deleted can be sometimes restored depending on various factors, however not by me. I'm sure there are many who could search for deleted files and probably restore them also, but again, it ain't me. ergo, inaccessible to me but accessible to others with talent.