Normal
I've sailed Carnival several times. One year we were upgraded from just a regular balcony cabin to a Penthouse Suite! Talk about spoiled! Now all other cabins look like closets to us. :lol But we've sailed Carnival 6 times and that's the only time it has ever happened. I'm booked on the Carnival Conquest this year and we booked a Cat. 11 suite (one grade down from Penthouse), but I'm sure that chances of us getting upgraded to a Penthouse again are slim.
