It is not so much a question of "listing" as one or the other, but it is a question of fairness and abiding ant-fraud laws when there is a competition for prize money. The competition has to be defensible as fair and its rules and structure are reviewed for compliance. Surely large producers will lawyer it to death for maximum wiggle room, but the essence of it being "fair" and not "rigged" is in tact. That was the core of the Stillman case and presumably why it got settled. Whether it was settled because her allegations were true, or the allegations of it being rigged were too damaging to air in public who knows? But if it was legally determined to be rigged, many contestants would have claims. But to your point it hasn't been tested (as far as we know), and if they were found to have run afoul of it all, they have piles of money to address such things.
The Survivor "rules" got leaked a while back and are pretty interesting, but you can clearly see the competition language of Contestant/Prize and detailed discussion of the competition rules (with huge "producer's discretion" caveats). You can also see language around not cheating (quid-pro-quos, losing in exchange for money, etc).
The Survivor rule book: the games rules, part of the cast contract, details consolation prizes, how ties are broken, prohibited behavior, and more.
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