Hmm, interesting question.
As a holder of an FCC General Class, you'd think I'd know that answer.
The fcc website www.fcc.gov
may be able to help.
In my personal opinion these radios are such short range that it probably will not be an issue. I'd say you should be more concerned with whether the cruise line would have any trouble with them. I'd still think you're safe since any of their [NCL's] portable communication is going to operate in a different band.
I'll see what I can dig up.