There is a problem within the pcre_fnmatch-Function concerning backslashes. Those will be masked by preq_quote and ADDITONALLY by the strtr if FN_NOESCAPE is not set -> something like "*a(*" will finally result in "#^.*a\\(.*$#". Note the double backslash which effectively does NOT mask the "(" correctly.
Since preq_quote always matches a backslash I don't think that this'll work with using preg_quote at all.