They can print all the fancy brochures laden with long-winded "policy" they like but until they prove they will follow and enforce their own guidelines it's just so much hot air. Hurtigruten had policy too that was promptly ignored by every level of its organization.
And the deal breaker for many countries will be this demand from the cruise lines.
Agreement to allow safe passage to SARS-CoV-2-infected individuals and their close contacts to debark and travel home.
The above is an attempt by the cruise lines to dump off any passenger who tests positive and make them the responsibility of the host country. No thanks.