"...they are competitors and would be taking business away from SWF..."
This may be true but there are times where businesses have to realize that consumers have far more choices and power than they once did. If someone buys from there LFS or some other place they can still buy at SWF.com in other words they may still be great customers. Policing, editing, posts for "commercial content" can get laborious and ridiculous at times (I am a mod on our reef club board) We just make sure no one is selling "commercially" it's not worth our time to stop any other posts or links unless they are obscene or contain SPAM. You can tell a comercial post from someone trying to give honest advice about what equipment they use and where it came from and someone posting "come on over to jimbosfishstore.com" (not an actual site) People talk on boards or off of boards, if not this one then others it's sad but in time that kind of censorship drives members away.
Just my opinion nothing more
That said, a thread detailing your favorite LFS should be no serious threat to anyone. In fact we had a similar discussion about what you are wanting to do here. We decided that only positive LFSs' should be mentioned on our board that way if it's not listed then it's prob not all that good
