The purpose of the cruise is a cruise. One which will bring together people who share a common interest.
One can engage in casual sex with strangers anywhere... you don't need to sail on a cruise to do that.
I guess STella has never heard of free will, or the right to say no. 
In her world, going on a cruise means 'must say yes to sex with strangers' 
in the words of Cary Grant
Judi Judi Judi
you really can't be that thick
has the bleeding stopped ?
would you like a bowl of milk ?