I don't think there is another particularly good solution that is simple
and does not rely on much user training/understanding. A few things you
could consider:
 a. put the objectives into a form field in a section on its own,
protect that section for form filling, and use a REF field in the
unprotected portion of the document to duplicate the text. The main
limitations are that working in a form field is different from working
with normal text - in particular, the user can't use normal formatting
features in the form field.
 b. stick with the ordinary bookmark approach but ensire that the users
have  Tools|Options|View|Bookmarks checked. At least then they can see
whether they are typing inside or outside thebookmark. (As far as I
know, they do have to delete the /entire/ bookmarked text to remove the
bookmark altogether).
 c. put the text in a separate file and INCLUDETEXT it. The original
text can be updated using ctrl-shift-F7. But still easy to get it wrong,
and the file contents would not be reset when the user created a new
document. Nice though if what you really want is for the user to edit
their /previous/ objectives, potentially nasty if you want to be able to
reprint old versions of the document with oder versions of the
objectives. You could probably achieve something similar using AUTOTEXTs.

Peter Jamieson