One thing I have noticed about this site is the number of threads that are locked, I've never been on a site with such prolific locking. It's kind of annoying.
On the other hand, being a mod on another site myself, I understand why they do as they do, although I do think they be a might triggerhappy.
It is important to have a clear guideline to follow and keep a firm hand however.
A suggestion, instead of locking some of the more trivial drivel threads or those in blatant violation of the T&C's, why not move them into the mods lounge? This keeps the forums from being cluttered up with locked threads, you have a record of the thread, and if a supermod or admin disagrees they are free to move it back, otherwise it slowly fades away neatly tucked out of sight and out of mind in the mods area, and we users don't have to keep tripping over them out in the public area.