I have also been trying to follow this new info, and trying to find out the truth instead of what people think is right.
This is what I found out from my TA's contact from Carnival. Anything used like a cpac needs to be hand carried on the ship, or attach a note in your luggage telling those looking, what it is for.
You might be called to the time out room for inspection. Power strips and extention cords will be collected, and returned to you after the cruise.
I do not need a C pac yet, but travel with a back massager that weights a ton, and unless I want to get rid of the back pain standing up, I will need an extension cord.