Margaritaville Cruise / what are my rights to bring food?

Has anyone cruised with Margaritaville ? My friend booked us a trip and I waited to the last minute to read the fine print - which includes that we can't bring a cooler or food - and now I'm terrified. Does the ADA apply at all? I'm waiting for a manager to call me back. Also, what counts as a "Doctor's Note"? Do I just bring a paper with my diagnosis on it ?