Its this kind of stuff that really pisses me off. Just like some people take tylenol because they cant take aspirin, there is no treatment that works for every single person on earth. I have about 6 different cardiac diagnoses and 2 of the lung. When I had to I could wear a mask for only about 30 minutes before I start gasping for air. You can have proof (even at your own doctors' office) but they dont care. They only comply with the rules given to them WITHOUT regard to the patient's needs. Yes, I would look into suing....even just a govt agency questioning Costco should make them ............ their pants.