Use :present as key for the absence validatior message

activemodel/lib/active_model/locale/en.yml

@@ -13,7 +13,7 @@ en:
       accepted: "must be accepted"
       empty: "can't be empty"
       blank: "can't be blank"
-      not_blank: "must be blank"      
+      present: "must be blank"
       too_long: "is too long (maximum is %{count} characters)"
       too_short: "is too short (minimum is %{count} characters)"
       wrong_length: "is the wrong length (should be %{count} characters)"

activemodel/lib/active_model/validations/absence.rb

@@ -3,7 +3,7 @@ module ActiveModel
     # == Active Model Absence Validator
     class AbsenceValidator < EachValidator #:nodoc:
       def validate_each(record, attr_name, value)
-        record.errors.add(attr_name, :not_blank, options) if value.present?
+        record.errors.add(attr_name, :present, options) if value.present?
       end
     end