If a referring page can't be update because it's locked (ex: someone's editing), it appears on an alert. You can missed pages later by again pressing Rename/move.
Note: Deleting means moving the topic to the Trash web. Since all webs share the one Trash, name conflicts may come up.
Added:
> >
Note: Keep in mind that moving a topic from a view restricted web to a public web or the Trash web will compromize security.