My MIL also humored one of those "you've won a cruise!" calls, just to see how it played out. First she had to answer some survey questions that seemed harmless enough, and then the guy said congratulations, you're all set up for your free cruise. We just need you to pay the port taxes of $78. MIl said no, you said it was a free cruise, why would I be paying anything? After a little back and forth, she was bumped up to the supervisor.
She said he explained why she would have to pay the taxes, but then it comes out that a) the cruise leaves from Miami, which is about as far from where MIL lives as you can get in the US, and b) it's a one night cruise. So she said, in addition to the port taxes, I would need to fly 3000 miles on my own dime to go on my "free" cruise for one night? No thanks.
Much like a time share spiel, the cruise might have actually been free, with lots of pressure to extend at your cost and/or be bombarded with sales pitches the whole time.