Even though the rules about one sale per week were relaxed, it seems like each day could only have one club making a sale, and there was still a queue for those days. He was saying that since his group had a 'precedent' of 'needing money' they still got priority in that queue. There is no guarantee that other groups were or weren't missing out on money. There is just isn't enough information to make that statement.

Yeah let's put it this way. Say school has no vacations so they used to get 52 sales a year, in which of course the clubs with a precedent of needing more money took precedence. Now say they now get 104, or hell... 156 sales a year because of the change in rules. Let's say that clubs that needed money took 80% of the days (this not changing in the worst case scenario), leaving 10 or 11 days for the rest of the clubs before, the remaining sales for this other clubs increases to 21 or 32 respectively.

The only way that the chess club was going to take away sales from the other clubs is if their percentage of sales increases, and even then it would have to increase beyond a threshold where it started eating up the extra days beyond the original sales the other clubs where having.

Sure it could be the case that other clubs where missing out, but it is very much more probable that everyone was benefiting from the chess club 'hack'.

Besides, you could argue that if your club does nothing to take at least some advantage of the relaxed rules it's the other clubs' fault, not the chess club's. In the end the clubs profited, the members profited, and the businesses that provided the food profited. This is a good compromise if X club didn't get much benefits after all.