i have one particular forum on my 7.2 boards that is writable by admins only, but viewable by everyone.

however, i've noticed its possible for mods to move threads into this forum, after the threads are created elsewhere.

is there anyway to globally prevent that?

The only way you can do it is to remove the ability of your moderators to move threads anywhere.

What I would actually do though is to inform your moderators that threads are NOT to be moved there.

Sounds like a possible bug to me, a check needs to be made to see if topics can be created by the user trying to move the topic into that forum.

You might report it at ubbcentral Rob and see what Rick thinks.