Index: trunk/data/validator/ignoretags.cfg
===================================================================
--- trunk/data/validator/ignoretags.cfg	(revision 9047)
+++ trunk/data/validator/ignoretags.cfg	(revision 9050)
@@ -39,5 +39,4 @@
 E:loc_name
 E:attribution
-E:admin_level
 E:heritage
 E:old_name
@@ -94,4 +93,5 @@
 K:bicycle=dismount
 K:wall=no
+K:man_made=petroleum_well
 ;
 ; Highway Key/Value Pairs
Index: trunk/data/validator/numeric.mapcss
===================================================================
--- trunk/data/validator/numeric.mapcss	(revision 9047)
+++ trunk/data/validator/numeric.mapcss	(revision 9050)
@@ -175,2 +175,9 @@
   assertNoMatch: "node amenity=cinema screen=8";
 }
+*[admin_level][admin_level !~ /^(1|2|3|4|5|6|7|8|9|10|11|12)$/] {
+  throwWarning: tr("unusual value of {0}", "admin_level");
+  assertMatch: "node admin_level=0";
+  assertMatch: "node admin_level=-1";
+  assertMatch: "node admin_level=13";
+  assertNoMatch: "node admin_level=5";
+}