Clarification - sitemap example on page 203 is a best confusing. A Sitemap node without url will not display and the duplicate urls will generate a compile error. Since the parent nodes generally have no pages, the workaround was to provide a url of ~/default.aspx with a unique query string.
The workaround is problematic since clicking on the parent node returns to home page. The parent nodes logically should have their url disabled and should only display their children.
Is there anyway to change this behavior.