diff --git a/usr.sbin/mergemaster/mergemaster.8 b/usr.sbin/mergemaster/mergemaster.8
index ab33b31eb974..4dcad39504ae 100644
--- a/usr.sbin/mergemaster/mergemaster.8
+++ b/usr.sbin/mergemaster/mergemaster.8
@@ -1,4 +1,4 @@
-.\" Copyright (c) 1998-2010 Douglas Barton
+.\" Copyright (c) 1998-2011 Douglas Barton
 .\" All rights reserved.
 .\"
 .\" Redistribution and use in source and binary forms, with or without
@@ -24,7 +24,7 @@
 .\"
 .\" $FreeBSD$
 .\"
-.Dd March 13, 2010
+.Dd August 9, 2011
 .Dt MERGEMASTER 8
 .Os
 .Sh NAME
@@ -244,6 +244,8 @@ or another directory you specify in your
 rc file.
 .It Fl U
 Attempt to auto upgrade files that have not been user modified.
+This option can be dangerous when there are critical changes
+in the new versions that affect your running system.
 .It Fl m Ar /path/to/sources
 Specify the path to the directory where you want to do the
 .Xr make 1 .
@@ -360,6 +362,7 @@ with all values commented out:
 #AUTO_INSTALL=
 #
 # Automatically upgrade files that have not been user modified (-U)
+# ***DANGEROUS***
 #AUTO_UPGRADE=
 #
 # Compare /etc/rc.conf[.local] to /etc/defaults/rc.conf (-C)
@@ -461,7 +464,7 @@ temporary root environment comes from Nik Clayton's
 make world tutorial which is referenced above.
 .Sh AUTHORS
 This manual page and the script itself were written by
-.An Douglas Barton Aq DougB@FreeBSD.org .
+.An Douglas Barton Aq dougb@FreeBSD.org .
 .Sh BUGS
 There are no known bugs.
 Please report any problems,
diff --git a/usr.sbin/mergemaster/mergemaster.sh b/usr.sbin/mergemaster/mergemaster.sh
index 4b20464b5f7c..78d5c08c49fe 100755
--- a/usr.sbin/mergemaster/mergemaster.sh
+++ b/usr.sbin/mergemaster/mergemaster.sh
@@ -5,8 +5,8 @@
 # Compare files created by /usr/src/etc/Makefile (or the directory
 # the user specifies) with the currently installed copies.
 
-# Copyright 1998-2010 Douglas Barton
-# DougB@FreeBSD.org
+# Copyright 1998-2011 Douglas Barton
+# dougb@FreeBSD.org
 
 # $FreeBSD$
 
@@ -30,6 +30,7 @@ display_usage () {
   echo '  -C  Compare local rc.conf variables to the defaults'
   echo '  -P  Preserve files that are overwritten'
   echo "  -U  Attempt to auto upgrade files that have not been user modified"
+  echo '      ***DANGEROUS***'
   echo ''
   echo "  -m /path/directory  Specify location of source to do the make in"
   echo "  -t /path/directory  Specify temp root directory"
@@ -635,7 +636,7 @@ case "${RERUN}" in
     # Only set up files that are crucial to {build|install}world
     { mkdir -p ${TEMPROOT}/etc &&
       cp -p ${SOURCEDIR}/etc/master.passwd ${TEMPROOT}/etc &&
-      cp -p ${SOURCEDIR}/etc/group ${TEMPROOT}/etc;} ||
+      install -p -o root -g wheel -m 0644 ${SOURCEDIR}/etc/group ${TEMPROOT}/etc;} ||
     { echo '';
       echo '  *** FATAL ERROR: Cannot copy files to the temproot environment';
       echo '';