Wondering if it would be feasible for you to add a 4th option to our report spam button. One which is report wrong forum.
Admittedly the mods tend to be pretty good at quickly moving threads into the correct forum if they've been wrongly posted, but a flagging tool might well be of use (as i've come across 3 just now which obviously need moving, yet are legitimate posts, so i don't want to report them as spam).
One other side thing - The first page of General talk seems to be 80% threads which have been moved. If the subscription to threads stays linked to its new location, do you really need to keep it there with a "moved" tag?
[an alternative would be to maybe have an auto email to the author which goes out saying your thread "Title" has been moved from forum X to forum Y, or somthing similar]