The purpose of this question is not to find out how SO protects its sitemap in order to subvert it, so to that end, I don't expect an exact answer.
However, questions around SO's sitemap have popped up:
Does Stack Overflow have a sitemap?
Given the initial statement (but hey, an exact answer would be accepted as well), is there any guidance or set of rules/experiences/info which would indicate what to look at when protecting a sitemap like SO's, dos and don'ts as well as the tradeoffs/risks involved?