A health disclaimer is required for every passenger on a cruise even before COVID as they can't afford for someone to be sick as it spreads round cruises super quick! And had hand sanitisers going into food areas long before it was around for COVID.
The fact that Nick had a dodgy stomach the day before (said so in the restaurant that he was eating 'light') , but he didn't declare that on the form either! Its one of those grey areas since he seems to suffer IBS it should be something he discloses but probably didn't as they didn't want to be denied boarding. Its like most food companies, if you have had the shits you need to be clean a full 48 hours before you can return to work.
Their lame excuse would have been that they weren't near the person who had COVID, but how could they have been sure!
If they were assholes enough to break the back to back cruises rule, why do we think they would disclose if they were sick?!