Index: src/wp-includes/option.php
===================================================================
--- src/wp-includes/option.php	(revision 31246)
+++ src/wp-includes/option.php	(working copy)
@@ -268,7 +268,7 @@
 	if ( $value === $old_value )
 		return false;
 
-	if ( false === $old_value )
+	if ( apply_filters( 'default_option_' . $option, false ) === $old_value )
 		return add_option( $option, $value );
 
 	$serialized_value = maybe_serialize( $value );
@@ -369,7 +369,7 @@
 	// Make sure the option doesn't already exist. We can check the 'notoptions' cache before we ask for a db query
 	$notoptions = wp_cache_get( 'notoptions', 'options' );
 	if ( !is_array( $notoptions ) || !isset( $notoptions[$option] ) )
-		if ( false !== get_option( $option ) )
+		if ( apply_filters( 'default_option_' . $option, false ) !== get_option( $option ) )
 			return false;
 
 	$serialized_value = maybe_serialize( $value );