The problem with that approach is that the ways in which they can avoid any liability beyond a full refund give sufficient latitude that there is a greater probability of them having no liability beyond the refund than there is of them actually having any liability, so it remains best advice to cover your risk by making sure the flights are within a package, or insuring your risk if they are outside a package.
So, yes, it is possible to conceive of a situation where the cruise line is sufficiently reckless to leave themselves open to damages, but it is more likely that they will not do that, so protect yourself and don't depend upon it ...