If you have travel insurance from any company, (including Princess) it would depend on what is covered in the policy. If you just decide not to go, the insurance probably wouldn't pay.
If you think there's a chance that a family member (or you) may become ill and you'll need to cancel, be sure that's covered. If you're concerned about missing the ship in a port, be sure the insurance covers that possibility.
You really just need to find a travel insurance policy that fits your needs.
Personally, I would never buy the cruise line's insurance. In the very unlikely chance that the line goes "under" there's a chance you'd lose everything.
"A truly happy person is one who can enjoy the scenery on a detour."
Golden Princess 2009Carnival Conquest&
Grand Princess 2010Island Princess&
Grand Princess 2011Carnival Magic&
Carnival Dream 2012Island Princess&
Carnival Magic 2013Carnival Legend 2014&
Carnival Magic & Coral Princess 2015
Carnival Liberty 2016