I truly hate the phrase that we're going to have to learn to live with it, but to some extent this is the truth. Masks alone don't work. We had a hotel based holiday in March/April where protocols dictated a supervised test 3 days before boarding the plane and again on arrival. Masks were worn just about everywhere and the vast majority of people did wear them. BUT 2 days on returning home hubby, daughter and myself came down with Covid!! Goodness only knows where we'd picked it up.
So what's the answer on a cruise ship? Your guess is as good as mine!!