This is what I found on Carnival website:
• Electrical devices such as fans, power strips, multi plug box outlets/adaptors, and extension cords will be removed if determined to pose a hazard and returned the last day of the cruise prior to debark.
Going over their banned items, I was really surprised to see dive tanks. What happens when you want to bring your own dive equipment?
Here is the link to FAQ which includes baggage restrictions:
Frequently Asked Questions, Information | FAQs | Carnival Cruise Lines
Here is another surprise:
• Fish Caught on Fishing Expeditions: The fish cannot be brought on board; it must be shipped home.
When we cruise and people have caught fish, they have often brought them back onboard to be cooked. Why go on a fishing expedition if you can't eat your catch?