Index: trunk/data/validator/unnecessary.mapcss
===================================================================
--- trunk/data/validator/unnecessary.mapcss	(revision 6769)
+++ trunk/data/validator/unnecessary.mapcss	(revision 6778)
@@ -10,4 +10,14 @@
   assertMatch: "way bridge=no";
   assertMatch: "way highway=proposed access=no";
+}
+
+area:closed[amenity ][area?],
+area:closed[building][area?],
+area:closed[landuse ][area?],
+area:closed[leisure ][area?],
+area:closed[natural ][area?],
+area:closed[shop    ][area?] {
+  throwWarning: tr("{0} is unnecessary for {1}", "{2.key}", "{1.key}");
+  fixRemove: "{2.key}";
 }