For a while, they were confiscating just about all fans with a cord. It really isn't black and white.
They still have on carnival.com
"• 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. "
That still leaves it up in the air and pretty much on a ship by ship, cruise by cruise basis.
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