Originally Posted by Jellby
I would not like a pop-up. It's annoying, and it only appears after one has already written the post (in that case, a likely reaction would be to post anyway, rather that write it again elsewhere).
I would prefer to replace the "Quick Reply" box (and "New Reply" button) with a warning, only by clicking away the warning (and hopefully reading it) should it be possible to write a reply.
I would find that more annoying to have to click a button every time I want to reply. How about when you start typing in your message in an old thread then it pops up and warns you?