Index: bp-blogs-functions.php
===================================================================
--- bp-blogs-functions.php	(revision 6829)
+++ bp-blogs-functions.php	(working copy)
@@ -56,8 +56,8 @@
 
 	if ( !empty( $blog_ids ) ) {
 		foreach( (array) $blog_ids as $blog_id ) {
-			$users       = get_users( array( 'blog_id' => $blog_id ) );
-			$subscribers = get_users( array( 'blog_id' => $blog_id, 'role' => 'subscriber' ) );
+			$users       = get_users( array( 'blog_id' => $blog_id, 'fields' => 'ID' ) );
+			$subscribers = get_users( array( 'blog_id' => $blog_id, 'fields' => 'ID', 'role' => 'subscriber' ) );
 
 			if ( !empty( $users ) ) {
 				foreach ( (array) $users as $user ) {