I know of two different sites where this happens. As has been said, just keep your head down and say nothing other than to exchange pleasantries and maybe a cuppa with your adjoining neighbours. It is sad that people on committees (not just allotment ones) are often very vindictive and spiteful and their clique "rules ok" Just regard them as sad people, and remember at the end of the day, they still have to go to the toilet Whenever I meet folk who are rude to me (which fortunately is seldom) I always look at them and remember that. It takes it down into perspective Mrs Bouquet
Are they? Certainly not in my experience. I am on three committees, know no-one who is vindictive or spiteful, and no-one who ever knew me would accuse me of having those traits.
I don't think there is an easy solution if the committee is corrupt, if you manage to get on the committee, it is you against everyone else, so can easily get outvoted on anything. What is needed is an authority above the committee who can be approached, but then it is going to be the words of one against the clique. The only thing I can think of if there is a higher authority with the power to act is to make a formal complaint, combined with a petition signed by everyone who feels the same way (if they are corrupt, many other plot holders will have similar feelings).