So I sent the organizers of the event an email and this was the response i got, and very quickly too
Thank you for getting in touch with us. We appreciate you taking the time to let us know about your concern.
As trade show organizers, we sometimes run into difficulty with the integrity or credibility of vendors who attend our show. While we do endeavour to book in bone fied, legitimate businesses, we really do not have a great deal of control over their business and how they conduct it. We have no ability to monitor the business pracitices of each vendor.
With regard to these specific exhibitors, we had done some investigation prior to the show, to ensure that they were not, as you say, "scammers", because everyone is aware of this potential with these sorts of "enter to win" opportunities. The evidence we found was that, while there was a similar business that was being accused of fraudulent practice, there was no evidence that this particular group was. To the best of our knowledge at this time, people do genuinely get to take a cruise with this group. But yes, they do also charge for it and yes, everyone who enters, wins. This is sometimes upsetting for people and we agree that getting the ongoing calls is not pleasant. We don't, though, have real evidence that they are fraudulent. However, they do not have a good reputation and we have received several complaints. It is not our intention to work with this particular vendor in the future.
You may wish to contact your phone service provider and have their numbers blocked.
Thank you again for your comments and we do hope that this allays your concern.
Business & Project Manager