Index: modules/field/field.info.inc
===================================================================
RCS file: /cvs/drupal/drupal/modules/field/field.info.inc,v
retrieving revision 1.56
diff -u -r1.56 field.info.inc
--- modules/field/field.info.inc	23 Oct 2010 15:55:04 -0000	1.56
+++ modules/field/field.info.inc	15 Dec 2010 00:33:17 -0000
@@ -605,7 +605,8 @@
  *
  * @param $field_name
  *   The name of the field to retrieve. $field_name can only refer to a
- *   non-deleted field.
+ *   non-deleted, active field. Use field_read_fields() to retrieve information
+ *   on deleted or inactive fields.
  *
  * @return
  *   The field array, as returned by field_read_fields(), with an