I meant exactly where you put it, thank you. I couldn't call them preview pages, because the same note is also at the bottom of the various "home pages" for the different sections, where you can add a post.

BTW, this footer would be useful in the "Comment on" page as well, before the first preview, and in general in all pages that let you edit something (like the pages showing a node made by "you", where you can update the post) - the only line that would not make sense there would be the first, referring to Where should I post X? :)