Last-chance warning when replying to old topics

Hello,

I’m running a community that historically has a bit of a problem with necro-bumping threads.

I am familiar with warn_reviving_old_topic_age (and we do have it set), but it seems that many users aren’t seeing the alert. We also don’t want to institute global topic timers because there really are use cases where reviving the old thread is useful.

Our previous solution was to block posting on an “are you sure” dialog based on this component:

however, both our necro-warning and the linked component above no longer seems to work (an out-of-the-box install of the admin-warnings thread allows me to post in closed topics unimpeded).

How should I proceed? I’m not afraid of getting my hands dirty and building my own component/plugin from the ground, but I’ve been struggling to find documentation on where to start.