that feature would be usefull to modify code on the fly.
my personnal usage would be to append/prepend <?php .... ?> when loading php snippet
and removing <?php / <? .... ?> when storing back in ckeditor,
as ckeditor either hides code when using protected source or remove code when not using protected source as it considers code as an unknown tag!
maybe be that feature will allow other usefull processing in other context...
thanx