diff --git a/lock b/lock
index ce2ca33..ac5a571 100755
--- a/lock
+++ b/lock
@@ -2,14 +2,21 @@
 
 # Yell if they are trying to lock remotely. This won't work.
 # Even if it does, it's wrong.
-if [ "${SSH_TTY}" ] ; then
+if [ "${SSH_TTY}" ] && [ -z "${STY}" ] ; then
 	echo "You're doing it wrong. Don't try to lock a remote computer."
 	exit 1
 fi
 
+# Graphically locking on Macs is simple.
+# If we're not in screen, attempt to graphically lock it.
+if [ `uname -s` = 'Darwin' ] && [ -z "${STY}" ] ; then
+	/System/Library/CoreServices/Menu\ Extras/User.menu/Contents/Resources/CGSession -suspend
+	exit
+fi
+
 # Handle non-graphical locking
-if [ -z $DISPLAY ] ; then
-	if [ -z $STY ] ; then # not running screen
+if [ -z "${DISPLAY}" ] ; then
+	if [ -z "${STY}" ] ; then # not running screen
 		if ( command -v vlock >/dev/null 2>/dev/null ) ; then
 			vlock
 			exit
@@ -22,12 +29,6 @@ if [ -z $DISPLAY ] ; then
 	exit 1
 fi
 
-# Locking on Macs is simple.
-if [ `uname -s` = 'Darwin' ] ; then
-	/System/Library/CoreServices/Menu\ Extras/User.menu/Contents/Resources/CGSession -suspend
-	exit
-fi
-
 # Try to lock sanely on X11.
 # Certain combinations of desktop managers and locking programs
 # allow new sessions to be started.