i personally like following the traditions of smart casual/business attire on regular nights and formal wear during formal nights. it is for me, a big part of cruising. and it does make me a little sad that some cruise lines are becoming more relaxed about this.
i think princess, for example, still enforces proper attire in the dining rooms. but when i first started cruising withe princess (many, many, many years ago) i also remember that on formal nights, there were restrictions as to areas of the ship where one could not enter without formal wear - not just the MDR's. i loved that policy!
the last time I cruise with princess, though, i saw that they did away with that part of the policy. still - they kept the policy for the MDR's. that's at least something.
anyway, while i've never been on a carnival cruise before, i have heard that it's more for a partying/fun-seeker crowd. i have heard that it's not for those that are looking for the more traditional sense in cruising.
which is why i probably will never sail with carnival. just my personal taste in cruising.
a lot of people have made some strong, valid points on both sides of the coin.
but definitely one that i agree with - if you want traditional formal dress codes, perhaps skip carnival cruises altogether.