Certain business models work better the closer the enterprise gets to reaching capacity. The goal is to fill every seat. Airlines understand that closing the cabin door is the end of the window of opportunity to sell seats. Once the flight departs they can offer high priced amenities but not seats for sale. Airline business models are based on projecting need and filling 99% of the demand (somebody always doesn’t show). If your cause thrives on capacity then the airline business models is ideal.
However, if your cause requires a deep personal connection then the capacity metric is not the preferred measurement for success. Open seats in an independent school classroom should not be sold at a discount to anyone willing to pay a last minute entry fee. Schools need students and families who are going to enhance the community experience. If they accept everyone using the airline capacity model there are sure to be conflicts. Purposes and expectations will clearly be misaligned. When the airlines board a passenger who in intoxicated and unruly the other passengers get upset with the airlines. They report via social media how they will never fly the airline of record again because of poor customer service quality. Airlines can afford to find more customers. Schools and deeply connected causes cannot. Therefore, get the right people on the plane. Leave a few seats open if you cannot find those ideally suited to join your cause. Individual experience is essential and creating scarcity and a waiting list are high quality problems.
Decide if your enterprise needs everyone or just a select few. Then get disciplined about your strategy.