sitemap.xml is expected to include absolutely all your public website pages. Google will sort them out as required.
I suppose your question is more likely to be in link with SEO than technology in itself. All my sites that rank well include all their public pages in their
sitemap.xml. I really do not think Google cares. It would find them anyway, so having them in the
sitemap.xml makes sense.
When I look at the statistics in the Google Webmaster tools, I can see that the it always says that about 10 to 20 pages are not included in their index. This is probably because they do not care about login, logout, thanks pages.
Since only robots are expected to read that file, it is safe to assume that if it includes boring pages, it won't hurt anyone.
However, if you can, add a priority and set it to a very low amount for those specific pages (like 0.1). That way it will probably rarely bother even looking at them. Without the As pointed out by Stephen in a comment, the frequency and priority parameters are now mostly ignored by Google. Instead the robot uses the last modification date to see what has changed compared against what they have in their index.
sitemap.xml, you have a way to give a weight to the page. So I think it is a powerful way to tell Google, don't bother too much about those.