The people absent from a decision can still be present in every consequence.

Decisions travel further than the rooms they are made in. The people who were not there, because they were not invited or not thought of, still live in the outcome, and their absence from the discussion has no effect on their exposure to the results. Representation is a matter of who bears the consequence, not who attends.

Before a decision is finalized, list who will feel it and check that list against who was consulted. Where someone is missing, either bring them in or make someone responsible for holding their interest in the room. It slows things down slightly. It is the difference between deciding with people and deciding about them.