Indeed, it's commonly used in logic. It's not any form of certainty though, just a rough way to compare probability. It does not mean either will happen, as there are undoubtedly many scenarios which are more dangerous and more likely.
That being said, one must account for Finagle's law, often miss-attributed as Murphy's law: What can go wrong will probably go wrong. A hyperbole, but makes a good point about not taking any probability as a certainty!