Removed "see section X" caution

Section is the next section after the caution, just 100px below

Author: wouterj

book/security.rst

@@ -709,12 +709,6 @@ URL pattern. You've seen this already in the first example of this chapter,
 where anything matching the regular expression pattern ``^/admin`` requires
 the ``ROLE_ADMIN`` role.
 
-.. caution::
-
-    Understanding exactly how ``access_control`` works is **very** important
-    to make sure your application is properly secured. See :ref:`security-book-access-control-explanation`
-    below for detailed information.
-
 You can define as many URL patterns as you need - each is a regular expression.
 
 .. configuration-block::