There are, of course, a number of cases where it's clear there isn't a dispute. The passenger is encouraged to work with the airline first, in order to ensure their complaint can be addressed by the carrier. When there isn't a resolution with the carrier directly, it goes to the agency for interpretation around the facts in that specific situation.
There can be facilitation to arrive at that conclusion, or there can be adjudication. It will depend on the specific set of facts that a carrier and traveller may find themselves with, in order to make a determination as to what the specific cause was—whether or not it was within control or had a linkage to safety.