The binary field shouldn't be stored by default, because it is already available in the _source.

src/main/java/org/elasticsearch/index/mapper/core/BinaryFieldMapper.java

@@ -59,7 +59,6 @@ public class BinaryFieldMapper extends AbstractFieldMapper<BytesReference> {
 
         static {
             FIELD_TYPE.setIndexed(false);
-            FIELD_TYPE.setStored(true);
             FIELD_TYPE.freeze();
         }
     }

src/test/java/org/elasticsearch/index/mapper/binary/BinaryMappingTests.java

@@ -0,0 +1,35 @@
+package org.elasticsearch.index.mapper.binary;
+
+import org.elasticsearch.common.xcontent.XContentFactory;
+import org.elasticsearch.index.mapper.DocumentMapper;
+import org.elasticsearch.index.mapper.FieldMapper;
+import org.elasticsearch.index.mapper.MapperTestUtils;
+import org.elasticsearch.index.mapper.core.BinaryFieldMapper;
+import org.elasticsearch.test.ElasticsearchTestCase;
+import org.junit.Test;
+
+import static org.hamcrest.Matchers.equalTo;
+import static org.hamcrest.Matchers.instanceOf;
+
+/**
+ */
+public class BinaryMappingTests extends ElasticsearchTestCase {
+
+    @Test
+    public void testDefaultMapping() throws Exception {
+        String mapping = XContentFactory.jsonBuilder().startObject().startObject("type")
+                .startObject("properties")
+                .startObject("field")
+                .field("type", "binary")
+                .endObject()
+                .endObject()
+                .endObject().endObject().string();
+
+        DocumentMapper mapper = MapperTestUtils.newParser().parse(mapping);
+
+        FieldMapper fieldMapper = mapper.mappers().smartNameFieldMapper("field");
+        assertThat(fieldMapper, instanceOf(BinaryFieldMapper.class));
+        assertThat(fieldMapper.fieldType().stored(), equalTo(false));
+    }
+
+}