Thanks for the interesting link Jerry, In our newspaper today there was an article about the original Queen Mary. The class sytem on that was rigourously enforced 1st , 2nd and 3rd passengers segregated. Liberace was travelling on her and didn't like that so he offered to perform for free provided only 3rd class passengers were allowed to attend. It doesn't say if Cunard accpted.
I would guess they wouldn't have wanted to upset their 1st class passengers.