It’s simply one of the rules of the thought experiment. If you bring in the hypothesis that Omega is cheating, you are talking about a different thought experiment. That may be an interesting thought experiment in its own right, but it isn’t the thought experiment under discussion, and the solution you are proposing to your thought experiment is not a solution to Newcomb’s problem.
It’s simply one of the rules of the thought experiment. If you bring in the hypothesis that Omega is cheating, you are talking about a different thought experiment. That may be an interesting thought experiment in its own right, but it isn’t the thought experiment under discussion, and the solution you are proposing to your thought experiment is not a solution to Newcomb’s problem.