A recent Commonwealth Fund survey reveals that nearly half of U.S. adults have received medical bills for care they believed was covered by their insurance. The survey highlights that individuals with health insurance frequently encounter unexpected medical expenses or denial of care. This issue has prompted California lawmakers to consider legislation that would require health insurers to maintain accurate listings of covered services, with penalties for non-compliance. The findings underscore the challenges faced by many insured, working-age Americans who are dealing with unforeseen medical costs and coverage denials for necessary treatments.