How about this for a scam?

You want to run a cruise so you retain a firm to do instant testing on the arriving passengers. Only people with clean tests can board. Everybody's happy. They can have a fun, relaxed cruise, just like the good old days.

Here's the kicker: the test is a scam. It gives everybody a clean bill of health. Oh, you could put in a few ringers to get flagged as positives and to be escorted out in tears by security, just to build credibility.

When it's all over and people start getting sick, they find the waiver they signed is ironclad and they have no legal recourse whatsoever. Besides you've has blown town and are nowhere to be found.