It's good that you make a distinction between success rate and safety rate.
However, safety rate doesn't need to be 100%. If you can keep the failure probability as low as the probability to be hit by a random asteroid falling from the sky, that's good enough.
However, safety rate doesn't need to be 100%. If you can keep the failure probability as low as the probability to be hit by a random asteroid falling from the sky, that's good enough.