Personally I would not wear a medical bracelet stating I have CFS or FM. The reason is that these diseases are controversial and can lead one to recieve less than adequate medical care in the emergency room. A prominent CFS physician emphasized that if CFS patients are seen in the emergency room they should not tell the doctor they have have CFS. He noted one patient of his who had been in a car accident and told the doctor he had CFS and was dismissed. He was later found to have a broken rib.
Since there's is no set protocol for treating CFS - and it s not thought to be life threatening - telling an emergency room doctor you have it doesn't help him/her treat your condition. Instead this doctor recommended that you stick to your symptoms and let them give you a full check up.