Index: docs/django-admin.txt
===================================================================
--- docs/django-admin.txt	(revision 5691)
+++ docs/django-admin.txt	(working copy)
@@ -400,6 +400,20 @@
 might be in ``INSTALLED_APPS`` by default. When you start a new project, run
 this command to install the default apps.
 
+.. admonition:: Altering existing tables
+   
+   ``syncdb`` will only create tables for models which have not yet
+   been installed; it will never issue ``ALTER TABLE`` statements to
+   match changes made to a model class after installation.
+   
+   This is because changes to model classes and database schemas
+   nearly always involve some form of ambiguity, and so Django would
+   have to guess at the correct changes to make. The risk that
+   critical data would be lost by doing so is simply too great, so
+   Django never attempts to automatically change your tables for you;
+   instead, you'll need to manually issue the correct ``ALTER TABLE``
+   statements if you need to change an existing table.
+
 If you're installing the ``django.contrib.auth`` application, ``syncdb`` will
 give you the option of creating a superuser immediately.