This type of approach is called protectionism, the Wikipedia article is pretty good and goes into the implications of it: https://en.wikipedia.org/wiki/Protectionism

That approach would still leave you weak to always picking 1 or 100. Without proof, I believe the optimal guessing strategy would perform equal (on average) for every number, to not give the opponent any standout choice (common for optimal strategies, but not always the case). If my math serves me right, that would be an average of log2(100) = 6.64 guesses for any number, which would make you lose 0.64$ on average.

Although upon further thinking, you could then sprinkle in some binomial searches to abuse the uniformity. So the -0.64$ is merely a lower bound.

You forget that the quick guesses bring you more than $1!

As the original article says, on average you can win $0.20. But that's indeed the upper bound if we speak of the adversarial number picking.

I wonder if there is a name for this. Antimetabole comes to mind but that usually requires two clauses. I suppose it is a "chiastic pattern" which is a more broad definition, which I believe also applies to smaller patterns although I have only seen it used for larger patterns like chapters.

There actually is a sextuple star system in the night sky. Castor looks like a single star but actually consists of three binary stars: two of them in a binary system that is itself in a binary system with the other binary star. I don't know if there could be a stable position for a planet that would never experience nights, but there is at least some reason behind the idea.

For stable, always day position, maybe the planet could be in L1 point between two suns?