Yes, I definitely have a forex free card.
Doing a bit of googling, it seems that some cruise companies may have rules requiring you to pay in currency of your credit card residence.
http://www.cruisecritic.com/articles.cfm?ID=1119
I don't know, I've never booked a cruise before.
Fooling around with tunnelbear, it seems their website quotes prices in Euros if you visit from Europe or the UK, they quote in dollars for everyone else. They are basically using a rate of 1.33 dollars to Euro.