I think it's great to lock the News forum. However I wanted to clairify (in case you can't tell from your logins) that even a registered user is not currently allowed to comment or reply on threads that exist already.
It is not clear from your locking posting if this is by design.. I read your posting as saying that normal users cannot create new threads, but can comment on existing ones. If this is the design, it doesn't currently work (at least for me...)
Thanks for your hard work!