Yeah: nonsense. Players-- or at least creative players-- are quite capable of making decisions when the world is not predictable, and part of that can be reflected in shifting rules. That's a basic conceit of certain settings, adventures, environs, in fact. Fey, demons, non-euclidean horrors....
A lack of predictability changes the calculus, it doesn't prevent it. If you can't deal with a DM changing things up and keeping you on your toes now and then, you could check out any number of fantastic computer games on the market.