No warnings about section heading markups

[SJaffa]

I'm looking to keep my Sphinx rst files tidy and want to check we are following the Sphinx style guide, particularly the guidelines on section heading markups, like using # under- and overline for the main heading, then * under- and overline, then = underline, and so on.

Currently I am seeing warnings about duplicate labels but not about the under/overline punctuation used to mark the section headings. Is this expected? Is section-punctuation checking not implemented?

Thanks :)