Better yet, find someone with asthma or COPD and have them get a doctor to verify that they can't wear a mask because they can't breathe through it.  (This is actually a real problem for people with severe lung disease.)  Then when Walmart denies them access to the store, have them sue the shit out of the chain for discriminating against people with medical conditions.  After a few multimillion dollar lawsuits, maybe they'll pull their heads out of their asses.