I agree that getting kicked off of a ball at Cooper at sunset would be frustrating. (Are any other anchorages as contested as Cooper?) This is why it's so important to have a monitored anchorage. I would expect management to dinghy out and confirm whether or not a boat was rightfully on a mooring well before sunset, ideally as soon as the tie up is attempted. If I had a reservation that I had to enforce myself by kicking another boat off of a ball after they've been limin' all afternoon, then it's not really a reservation.