sitemap.xml for auth sites

No, it can only crawl public pages.

The reason that I ask is that I found one page out there in the wild that were talking about creating a user account for crawlers with read-only permissions. The idea was to in a public file instruct a crawler to login with that accounts username/password. Maybe not a good practice from a security point of view, but maybe seo-friendly.
Also, if you use something like Google Analytics, at least Google gets the uris from the logged-in pages. I wonder if that could confuse google. I mean I have my sitemap with non-loggedin uris only, but google sees that the page has much more uris than mentioned in the sitemap.xlm.