I think you can only get cancel for any reason coverage if you buy when you book your travel. I've only bought this coverage when all the swine-flu hoo haa was going on. I'm not sure if this is true, but it may at least effect the policies available.
All I ask is a tall ship and a star to steer her by; John Masefield
Carnival: Glory 2004, Destiny 2008, Splendor 2009, Freedom 2011, Valor 2012, Dream 2013
Celebrity: Summit 2011
Princess: Ruby 2010, 2014, Caribbean 2013, Coral 2014, Regal 2014, 2016
Sail Windjammer: Mandalay 2017
Star Clippers: Royal Clipper 2015