I am overposting, but for a good cause. This is a very important observation that goes far beyond broadcasting organizations - every community organization faces similar problem. The community organization of which I am a part faces a very similar problem - there is a loon who packs meetings a bunch of followers trying to take over the board - so far unsuccessfully due to a technicality - but the danger is real. As Doug said, the constituency is fluid and it does not take much to take over the board and drive away everyone else. There are a lot of self-styled activists with control envy out there and these people are very crafty at disrupting democratically run organizations.
Some organizations protect themselves by establishing formal membership and membership dues - which drives most of the loons out, but many members oppose such a solution as undemocratic. So far, the community association I am a part of resisted that solution, but the board is divided.
However, I see it as a good solution - if you care enough something, you should contribute to its upkeep - so the membership due is not necessarily undemocratic, but it does raise the cost of loons bringing their goons in to cause havoc. Another way it have a nominating committee that sees to it that all interests are represented and the slate is not packed with loons from one camp.
Wojtek