I am sure that both Stan and John and right, the clay charge will no doubt cover the cost of shooting....if shooters turn up!
The vendors and shooters are mutually supportive financially: the former in terms of sales and the latter in terms of security for the organisers.
The vendors have to pay months in advance and it is this money which gives the organisers the financial security to lay on the organisation to accommodate a, hopefully, large number of shooters.
If the weather forecast is terrible for a day, or worse still, the whole weekend, many shooters will give it a miss but the trappers, food, equipment must still be paid for.
I have seen this situation at Maryland, Rhode Island and Sanford and although rain can drive shooters into the tents, it is noticeable how quiet a forecasted wet day can be.
If you haven't had to commit by virtue of a long drive, why get your pride and joy wet if you are not looking to make purchases: 'There is always next weekend to shoot.'
I am not looking to devalue the contribution to the event that shooters make: without them it would pointless for everyone. But it serves no one to forget the importance of the vendors to the financial viability of an event on this scale.