phranque - 3:52 pm on Aug 25, 2012 (gmt 0)
a sitemap is simply a url discovery mechanism.
reqardless of how a crawler has discovered a url, the robots.txt file is consulted to see if the url matches an excluded pattern before requesting the url.
GWT should report this as crawl "error".
i wouldn't recommend putting excluded urls in a sitemap.xml file.