Now, however, pretend there was a way to cheat so that you will have technically done X but in a way that is much, much easier than you previously thought. From an outside viewpoint once you have done X you are less likely to die even if doing X doesn't change your inside view of anything. So should you cheat to accomplish X?

I still don't see how it makes you more likely to be able to do X. The gladiator isn't trying to have his name engraved, he's trying to survive. Likewise, we aren't trying to get our messages heard by foreign civilizations, we're trying to survive whatever the Great Filter is (assuming it lies before us).

This looks to me like a case of Goodhart's Law: when a measure becomes a target, it ceases to be a valid measure.

(Oh also, I just thought: by the same reasoning, the gladiator should expect something to stop him from being able to get his name engraved via bribery, since he would reason that previous gladiators in his position would do the same thing, and he still doesn't see any names.)