The millennium in which my CEO can call me from any phone in the company and I'd be hard pressed to tell if it's legit or not? Or from a phone in another parent

The millennium in which my CEO can call me from any phone in the company and I'd be hard pressed to tell if it's legit or not? Or from a phone in another parent or subsidiary in any number of countries that I have basically no chance of recognizing? The simple fact that it's the CEO calling discourages anyone from questioning it because C level executives and senior management have a way of imposing this kind of "absolute authority" in many companies.