Yes. She should make much of the fact that Carnival sold her room, thus not encurring a full loss. Why should Carnival get paid twice for the same cabin? She should negotiate to pay only what they actually lost.
(Hmm — I wonder if whoever ended up with the cabin is the one who cancelled her reservation, then bought it at a last minute discount.)
That said, an idiot who posts their booking number, etc. on Facebook doesn’t get full sympathy.
“Why should Carnival get paid twice for the same cabin? “
Why one should read the article ...