I guess I have to admit I'm confused by the question. If I read it correctly, the contention is that some of us post only to threads containing exclusively posts by others in the same geographical area. (I mention posting rather than communicating, as anyone can read any thread without our knowing about it, thus communication can occur that no one but the individual reader is aware of.) This raises numerous questions:

Is it known for a fact that said people are indeed posting only to these particular threads (in other words, has EVERY recent post by these folks and/or EVERY recent thread been scrutinized)?

If so, so what? (Not meaning to be disdainful, rather wondering what, if any, difference does it make to anyone.)

What is meant by "shut a thread down"? (What I would expect it to mean is something I've never seen happen.)

selby, some clarification please?