We are scheduled to arrive mid-November but we just learned a member of our party may have a weakened immune system--if he does, the dr said that if he were to contract some sort of gastrointestinal illness as people experience in Mexico, he would not be able to recover. Naturally, we already book our flights, and paid in advance for two rooms for 6 nights at the Ritz with no cancellations and no refunds, and no insurance. I did explain that we were not going to leave the hotel while there, but this doctor said she knows people who have gotten cholera at the Westin in Cancun. I was surprised, b/c before I booked this trip I called the Dr's office to ask if we needed special immunizations and was told no, that if we were going to stay on resort property and not go to any rural areas we would be fine. Has anyone out there experienced "Montezuma's revenge" or the like at the Ritz?