My study organises a hackathon (12 pm to the next 12 pm so 24 hours total) every year and doesn't allow to bring your own coffee machine. Last year, the teachers machine was used but it's so freaking slow (produces one pot an hour or so) that we could hardly get any. Then, at the early night, it broke down. Everyone was going pretty insane without caffeine for that timespan haha. (Loads of people didn't bring energy drink because 'coffee at location' xD)