“Although CDC invariably garnishes the argument with dire prospects of ‘transmission’ of COVID-19 aboard a cruise vessel, these dark allusions dismiss state and local health authorities, the industry’s self-regulation, and the thorough and costly preparations and accommodations by all concerned to avoid ‘transmission’ and to confine and control the ‘transmission,’ if one occurs,” Merryday wrote. “In other words, CDC can show no factor that outweighs the need to conclude an unwarranted and unprecedented exercise of governmental power.”