How can one balance everyone's good? In order to do so you would need to be able to take the world in its entirety as those in the thought experiment do. We can't do this, so the suggestion is that we trust what people want. The problem is not only do people not have the foresight to know what they want their wants change relative to their haves. 'Need' would have been a better choice with a given definition. Because we can not balance everyone's good I suggest everyone must be chiefly responsible for themselves and their charges. They should be expected to be honest about their desires and, to be fair to others, they should be as little burden as possible. Such that the greatest good is caring for ones own needs first while avoiding hindering others from acquiring their own base needs. The only thing needed now is a definition of 'need', but I would probably just choose a level on Maslow's hierarchy.
I probably communicated as poorly as the author, so my point is: communication is an interesting problem, and these are week assumptions and poorly communicated as it is too easy for an alternate, though in my case similar, theory of ethics to be built.
I have friends who, to save money, break into buildings on the MIT campus to steal food and drink and naps and showers. They use the money they save to promote the public good. It seems like these criminals, not the average workaday law-abiding citizen, should be our moral exemplars
What if every student, faculty member, staff member, alumnus, and donor want food, drink, and grounds to be used in an ordered way. How are their collective wants less important than some few "poor" people? I don't see how that jump was made.