Index: trunk/data/validator/geometry.mapcss
===================================================================
--- trunk/data/validator/geometry.mapcss	(revision 15961)
+++ trunk/data/validator/geometry.mapcss	(revision 15964)
@@ -305,4 +305,10 @@
 }
 
+/* #18817 */
+way[man_made=pipeline][location=underground] > node[marker],
+way[power=cable      ][location=underground] > node[marker] {
+  throwWarning: tr("{0} node connected to an underground object", "{0.key}");
+}
+
 way[junction=roundabout]:righthandtraffic:clockwise,
 way[junction=roundabout]!:righthandtraffic:anticlockwise {