Our Xinyi-Dao disciples in Seattle (Manoj and Andrew) show the danger of strictly following the classical position of keeping your head upright as if it was being suspended by a string.  In olden times people fought with weapons that increased their striking and blocking ranges.  As a result, keeping their heads upright wouldn’t necessarily put them in any extra danger.  However, keeping your head upright in a scrap will most likely get you knocked out.  In modern times, you gotta protect your head!