If you use chkfontpath to delete all of the directories in the font path, and then try to add a directory, it does not add the directory. This is with version 1.7-2 (which I just upgraded to). An earlier version, under the same test, would add the directory to /etc/X11/fs/config but fail to precede it with "catalogue =", which resulted in the directory not being recognized.
fixed in version 1.8, available soon in rawhide.