Index: trunk/resources/data/validator/deprecated.mapcss
===================================================================
--- trunk/resources/data/validator/deprecated.mapcss	(revision 16278)
+++ trunk/resources/data/validator/deprecated.mapcss	(revision 16316)
@@ -1967,2 +1967,16 @@
   group: tr("deprecated tagging");
 }
+
+node[amenity=bench][capacity][!seats],
+way[amenity=bench][capacity][!seats] {
+  throwWarning: tr("{0} is deprecated for {1}", "{1.key}", "{0.tag}");
+  suggestAlternative: "seats";
+  group: tr("deprecated tagging");
+  fixChangeKey: "capacity => seats";
+}
+node[amenity=bench][capacity][seats],
+way[amenity=bench][capacity][seats] {
+  throwWarning: tr("{0} is deprecated for {1}", "{1.key}", "{0.tag}");
+  suggestAlternative: "seats";
+  group: tr("deprecated tagging");
+}
Index: trunk/resources/data/validator/ignoretags.cfg
===================================================================
--- trunk/resources/data/validator/ignoretags.cfg	(revision 16278)
+++ trunk/resources/data/validator/ignoretags.cfg	(revision 16316)
@@ -137,4 +137,5 @@
 E:amperage
 E:capacity
+E:seats
 E:cables
 E:circuits
Index: trunk/resources/data/validator/numeric.mapcss
===================================================================
--- trunk/resources/data/validator/numeric.mapcss	(revision 16278)
+++ trunk/resources/data/validator/numeric.mapcss	(revision 16316)
@@ -254,4 +254,6 @@
 
 /* must be an integer positive number only and not 0, see #10837 (lanes), #11055 (screen) */
+node[seats][seats !~ /^[1-9]([0-9]*)$/][amenity=bench],
+way[seats][seats !~ /^[1-9]([0-9]*)$/][amenity=bench],
 way[lanes][lanes !~ /^[1-9]([0-9]*)$/][highway],
 way["lanes:backward"]["lanes:backward" !~ /^[1-9]([0-9]*)$/][highway],