If only it were that easy, if you do that, the managers will be grateful certainly, but they will also endlessly demand more proof and validation that the system is now completely safe from certain doom until they feel comfortable, which is never. In a lot of cases it's simply easier to convince them that the system was never vulnerable to certain doom in the first place, because you were of course already 5 steps ahead of this even in the planning stages, and for some reason they have an easier time accepting that, as long as they still have every reason to believe you are a brilliant tech god who would never personally fall victim to such a common vulnerability. I suppose it's really less about the reality of the situation and more about what kind of corporate image you are cultivating and maintaining for yourself.