diff --git a/share/man/man3/queue.3 b/share/man/man3/queue.3
index 3e1a8062ef5f..256c0679e6b7 100644
--- a/share/man/man3/queue.3
+++ b/share/man/man3/queue.3
@@ -1,4 +1,4 @@
-.\"	$NetBSD: queue.3,v 1.38 2008/05/02 18:11:05 martin Exp $
+.\"	$NetBSD: queue.3,v 1.39 2008/10/07 13:03:50 apb Exp $
 .\"
 .\" Copyright (c) 2000, 2002 The NetBSD Foundation, Inc.
 .\" All rights reserved.
@@ -53,7 +53,7 @@
 .\"
 .\"	@(#)queue.3	8.1 (Berkeley) 12/13/93
 .\"
-.Dd December 11, 2007
+.Dd October 7, 2008
 .Dt QUEUE 3
 .Os
 .Sh NAME
@@ -1171,6 +1171,12 @@ while (CIRCLEQ_FIRST(\*[Am]head) != (void *)\*[Am]head)
 if (CIRCLEQ_EMPTY(\*[Am]head))		/* Test for emptiness. */
 	printf("nothing to do\\n");
 .Ed
+.Sh NOTES
+Some of these macros or functions perform no error checking,
+and invalid usage leads to undefined behaviour.
+In the case of macros or functions that expect their arguments
+to be elements that are present in the list or queue, passing an element
+that is not present is invalid.
 .Sh HISTORY
 The
 .Nm queue
diff --git a/share/man/man3/tree.3 b/share/man/man3/tree.3
index b78df99aa191..99bbf28b99a6 100644
--- a/share/man/man3/tree.3
+++ b/share/man/man3/tree.3
@@ -1,4 +1,4 @@
-.\"	$NetBSD: tree.3,v 1.3 2004/04/14 11:05:19 pooka Exp $
+.\"	$NetBSD: tree.3,v 1.4 2008/10/07 13:03:50 apb Exp $
 .\"	$OpenBSD: tree.3,v 1.9 2003/05/20 09:13:38 jmc Exp $
 .\"/*
 .\" * Copyright 2002 Niels Provos <provos@citi.umich.edu>
@@ -29,7 +29,7 @@
 .\" * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 .\" * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 .\" */
-.Dd February 24, 2002
+.Dd October 7, 2008
 .Dt TREE 3
 .Os
 .Sh NAME
@@ -416,6 +416,12 @@ The
 .Fn RB_EMPTY
 macro should be used to check whether a red-black tree is empty.
 .Sh NOTES
+Some of these macros or functions perform no error checking,
+and invalid usage leads to undefined behaviour.
+In the case of macros or functions that expect their arguments
+to be elements that are present in the tree, passing an element
+that is not present in the tree is invalid.
+.Pp
 Trying to free a tree in the following way is a common error:
 .Bd -literal -offset indent
 SPLAY_FOREACH(var, NAME, head) {