Some configuration options such as xmlrpcuser, iexssprotect, htmlok etc. have -- for good reasons -- security warning signs attached to them on the configuration page.
I suggest to add a warning sign to the fullpath ("Reveal full path of pages in the footer") option, too.
In general, the full path should never be revealed. But switching the fullpath option actually causes only a small visual change which might be easily missed, or an admin might have enabled fullpath for debugging purposes and later forgets to change it back. Also some people might underestimate the severity of this option.
[This report also refers to http://forum.dokuwiki.org/thread/6312