How do you get your CEO to pay for the monitoring and other breach preparation if you've just told him that "We have air-tight security, we cannot get hacked"?

How do you get your CEO to pay for the monitoring and other breach preparation if you've just told him that "We have air-tight security, we cannot get hacked"? CSO: We have airtight security, we cannot get hacked. CEO: Great! CSO: Please approve and fund this plan to handle a breach in case we are hacked. CEO: But you just told me we can't get hacked. CSO: Right, it's impossible. CEO: So why do we need to spend money preparing for it? CSO: Just in case. CEO: Just in case what? You just told me it can't happen. That seems a little like asking for money to prepare for an alien invasion or a zombie attack.