so if the premises is run by the college, its safe to say that they have been running the bar for a while. I can assure you that they knew exactly what they were doing when they ordered 400ml plastic cups. Those cups come in all sorts of sizes, it was a deliberate move to elect that size of a measure, and the person in charge would be making a killing from it.
I think you have a responsibility to expose this sort of activity. Not only is it illegal, but it is deliberate and immoral.