Example: https://codegolf.stackexchange.com/a/179329/83048
As you can see, it extends out of the box the post is contained within and mildly interferes with the HNQ.
For example:
\$ThisisademonstrationofwhathappenswhenyouusetoommuchLaTeXononelineNoticehowitgoesoffoftheboxthepostiscontainedin\$
post-layout
class doesn't haveoverflow:hidden
, just in case something (and not just MathJax) somehow manages to spill over the box. \$\endgroup\$