Index: docs/topics/templates.txt
===================================================================
--- docs/topics/templates.txt	(revision 16786)
+++ docs/topics/templates.txt	(working copy)
@@ -97,6 +97,18 @@
         * Method call
         * List-index lookup
 
+    This can cause some unexpected behavior with objects that override
+    dictionary lookup. For example, consider the following code snippet that
+    attempts to loop over a ``collections.defaultdict``::
+
+        {% for k, v in defaultdict.iteritems %}
+	    Do something with k and v here...
+        {% endfor %}
+
+    Because dictionary lookup happens first, that behavior kicks in and provides
+    a default value instead of using the intended ``.iteritems()``
+    method. In this case, consider converting to a dictionary first.
+
 In the above example, ``{{ section.title }}`` will be replaced with the
 ``title`` attribute of the ``section`` object.