Life insurance comes to mind. The premium charged is based in part upon
their expectation of how long you will live. Perhaps the cruise lines
have taken the possibility of a hurricane or breakdown into
consideration when pricing the ticket.
That claim has been made in this debate, but prices fluctuate so
widely it's hard to be certain. It appears to me, from a brief glance
at Carnival prices on Orbitz, that price is more correlated with
whether or not school is in session than it is with hurricanes.
It might make cruisers happier if Carnival (and others) said "The
price is $X, and if we have to deviate because of a hurricane the
price will be 80% of $X". Make it clear that the price is lower if,
and only if, there's a hurricane. Bad weather insurance, more or
less.