I set up my site to trigger the deletion of nodes, following the Rules tutorial, but changing the action from Publish to Delete. I created a test node and then ran cron manually, which triggered the action to delete the node. I received these messages:

 * Podcast TEST has been deleted.
 * Cron ran successfully.

and this error message:

user error: Negative changecount value. Please report this to http://drupal.org/node/516928.
array ( 'type' => 'node', 'id' => '29821', 'subtype' => 'podcast', 'loc' => 'node/29821', 'status' => '1', 'status_default' => '1', 'status_override' => 0, 'priority' => '0.5', 'priority_default' => '0.5', 'priority_override' => 0, 'changefreq' => 0, 'changecount' => -1, 'lastmod' => 1292444124, 'access' => true, 'language' => '', ) in /Library/WebServer/Documents/westport_library/sites/all/modules/xmlsitemap/xmlsitemap.module on line 616.

I did not report this to the issue in the error message because it seemed unrelated to me ("Query error after node creation with PostgreSQL").

The node is retained in the XML sitemap even after re-running cron, but a node I manually deleted was removed