When I first had trash implimented it was to cure a problem. I saw that deleted posts, were in some parts of the forum, filling up the first page of that section, and being a mod at the time it was annoying just looking at loads of deleted posts (that only mods could see). So, I had the idea of creating 'trash' as a place to move the deleted posts so that they wouldn't obscure relevant 'open' posts in the viewpoint of mods and admin.
Trash wasn't implimented for misplaced posts, mods should be helping members by moving a misplaced post to the correct part of the forum. Not everyone initially understands the structure of a forum, and new users should be helped out, they will soon find the correct place to post, and might even stick around..