Simon says, “Make sure a job can be done before holding anyone responsible for it.”
Now there is a no-brainer for you. Who but an idiot would hold someone responsible for a job that cannot be done? Alas my friend, if idiots could fly, many so called leaders would have their own airports. Have you ever seen a project fail and someone reflexively gets reprimanded or fired? Never mind the project’s history of success was limited to visions in someone’s mind. It happens on a grand scale and in little situations; but expecting the impossible and holding someone accountable happens often and repeatedly.
It will not happen with you and Simon, though. You will be expected to try, to give it your best. You will not be held responsible for its not working out, though, unless Simon can objectively confirm it was doable.