Carnival had a rule about what you could bring. They did not in force that rule. As time went by, the rule was stretched further and further. Now people are making it seem like these are new rules. It the same rule.
I can understand about bring soda on the ship. When our school system signed a coke contract, we had to agree to get rid of all non coke products.
Some people say that Carnival can't tell them what they can bring. Yes, they can. It's their ships, and they have that right. Try taking a case of beer into a stadium.
I was reading on line about a huge todo in New Orleans. Hours spent going through bags, and probably thousands of dollars worth of drinks confiscated.
It is usually always best to follow the rules then none of this matters.