It means you must have two bootable volumes on your computer and be logged on to the second bootable volume in order to delete the file.
Shades of booting into OS 9 to delete stuff from early versions of OS X!
It also means deleting the file could easily would probably render the volume unbootable and it would have to be reinstalled, and the advice you received to leave it alone is sound. (Personally I would never attempt deleting such a file (unless I suddenly developed an irresistable compulsion to erase and reinstall the system from scratch.
I've had a couple of exchanges with FAF's dev, and I've found him to be extremely conservative about stuff like this, his attitude (wisely) being "if you need to ask, I'm not going to empower you."
I run FAF in root mode by default, and although I'm certain that Rita's recalcitrant file can be deleted by root user, Thomas would never put that in writing.
PS: When I trash an app, I delete
every file it's planted, regardless of its location in my OS, and I've
never run into an issue.
