Borderline? How isn’t it criminal?

Disclaimer: I am not a lawyer and I am not your lawyer.

Salespeople lying, within certain limits, does not seem to be treated as fraud by most governments, caveat emptor and all.

If they tell you the alcohol on the cruise will be free and you sign a contract saying so, and then it actually isn’t and you have to pay more, that’s one thing. If they tell you it’s going to be sunny and warm when you’re taking a cruise to Alaska in winter, that’s a different thing.

Lying or deceiving during sales about things other than the product is a large part of a salesperson’s job, I believe (including but not limited to making the customer think the salesperson likes and respects them).

Saying “demand is high in Caribbean” is fine since the definition of demand is subjective. Saying coronavirus doesn’t affect warm weather places is criminal.

The issue is that any competent law firm will pull up articles and comments by officials stating that warm weather will dampen or hinder COVID-19 spread. They would only need to pull up a video of Trump stating as much and make a case that it's "reasonable" to believe the president.

And even more serious sources basically say: "we don't know at this time", which is not enough to make these actions criminal (as per current laws, per my limited unprofessional understanding).

Then again, who is stupid enough take medical advice from a vacation salesman? These customers have agency and are ultimately the decision makers. What this company is doing is unethical, but we all need to be responsible for the decisions we make. If I decide to go on a cruise right now, knowing what has been going on, it’s not the company’s fault if I get sick.

Sure, but scamming the gullible is still both criminal and immoral. And similarly intentional dangerous misrepresentation of facts like this should be criminal (and maybe already is, I do not know American law that well) even if you would have to be an idiot to actually believe it.

It's not really medical advice in the sense someone would normally think of it, it's vacation safety advice. While one should probably treat the words of any salesperson with extreme skepticism, a lot of people don't, and those most at risk (the elderly) use the official word of their cruise company as their main source of safety advice (usually of the form "get this vaccination" or "beware this part of town" or "this kind of tour operator on shore is a scam"). And regardless, salespeople are absolutely expected to be responsible for the claims they make, regardless of one's views on how much they should be trusted.