Index: trunk/data/validator/deprecated.mapcss
===================================================================
--- trunk/data/validator/deprecated.mapcss	(revision 13290)
+++ trunk/data/validator/deprecated.mapcss	(revision 13320)
@@ -1185,2 +1185,12 @@
   fixAdd: "transformer=yes";
 }
+
+node[tourism=picnic_table],
+node[amenity=picnic_table],
+node[leisure=picnic],
+node[leisure=picnic_site] {
+  throwWarning: tr("{0} is deprecated", "{0.tag}");
+  suggestAlternative: "tourism=picnic_site";
+  suggestAlternative: "leisure=picnic_table";
+  group: tr("deprecated tagging");
+}