I was reading this post from Kookaset in the suggestions thread:
Maybe posting the rules in a little more obvious place. It’s low on the pinned sections, but in my opinion, more important than most.
Perhaps a banner across the top of the screen, promoting the rules post?
In the moderator CP, we have the ability to create “Announcements”. Announcements appear above all of the other posts in their own section in whichever forum you wish to put them in. We could put Rules as a global announcement that is available in all forums.