TBH, I got bitten by this assumption. Once, in the course of many decades. A single flipped bit - in a place where it never could happen in the program. After c

TBH, I got bitten by this assumption. Once, in the course of many decades. A single flipped bit - in a place where it never could happen in the program. After checking everything up and down the stack, this was our conclusion: "the issued command was invalid, thus caught and aborted; the higher-level operation was rolled back, retried, and succeeded; impact: some insignificant delay; root cause: probably cosmic rays; probability of repeating: infinitesimal. Result: no point in guarding against that." (Note that this was in normal athmospheric conditions, not in deep space, hence the probability.)