Dusty no one will trade more than two either unless you make them like some years (had to trade 5) or if you actually explain the odds of what you can get by trading in more than one or there are people like me who take risks and trade 9 for gold gralat. Human nature is cheap so it will keep trading likely two but if more candy is obtained (preferable in other ways then ghosts and goblins that doesn't have 50 people in one spot)then more candy will be traded in.