Underhanded c contest (someone linked it in a comment) is a good example of how proofreading doesn't work. Other issue is that you can't conceivably check like this something with the size of many terabytes yourself.

The apparent understandability is a very misleading thing.

Let me give a taster. Consider a weather simulator. It is proved to simulate weather to specific precision. It is very straightforward, very clearly written. It does precisely what's written on the box - models the behaviour of air in cells, each cell has air properties.

The round off errors, however, implement a Turing-complete cellular automation in the least significant bits of the floating point numbers. That may happen even without any malice what so ever. And the round off error machine can manipulate sim's large scale state via unavoidable butterfly effect inherent in the model.

I'm not exactly sure why this matters.

I mean, OK, suppose you're right that it's possible that the world might turn out to be set up in such a way that we can keep the "upper hand" against a superintelligence. Suppose further that there is a "central dogma" here that contradicts this, and therefore that central dogma is wrong.

OK. Granting all of that, what choices ought I make differently?

One obvious example is chess playing from a significantly better position. No superintelligence has any chance against only a good human player.

Can you prove that the board position is significantly better, even against superintelligences, for anything other than trivial endgames?

And what is the superintelligence allowed to do? Trick you into making a mistake? Manipulate you into making the particular moves it wants you to? Use clever rules-lawyering to expose elements of the game that humans haven't noticed yet?

If it eats its opponent, does that cause a forfeit? Did you think it might try that?