Index: head/etc/defaults/rc.conf
===================================================================
--- head/etc/defaults/rc.conf
+++ head/etc/defaults/rc.conf
@@ -695,6 +695,7 @@
 ### Jail Configuration (see rc.conf(5) manual page) ##########
 ##############################################################
 jail_enable="NO"	# Set to NO to disable starting of any jails
+jail_confwarn="YES"	# Prevent warning about obsolete per-jail configuration
 jail_parallel_start="NO"	# Start jails in the background
 jail_list=""		# Space separated list of names of jails
 jail_reverse_stop="NO"	# Stop jails in reverse order
Index: head/etc/rc.d/jail
===================================================================
--- head/etc/rc.d/jail
+++ head/etc/rc.d/jail
@@ -147,7 +147,8 @@
 	#
 	# To relieve confusion, show a warning message.
 	#
-	_confwarn=1
+	: ${jail_confwarn:=YES}
+	checkyesno jail_confwarn && _confwarn=1
 	if [ -r "$jail_conf" -o -r "$_jconf" ]; then
 		if ! checkyesno jail_parallel_start; then
 			warn "$_conf is created and used for jail $_j."