You would be suprised how strict the company rules are for any ship operating in international waters. The casino especially, is in business to make money, but if it gets a reputation for ripping people off, word travels fast, and they would soon be out of business.
Sometimes it's harder than operating land-based, because people think they are going to get scammed before they even sail!
As with any business, there are some bad apples, but usually they do not last too long. People are not going to frequent the ship if the machines don't pay, or they cannot win on the tables!
I've worked on 24 ships, and only come across one company that tried to "rob" people on board - I worked there for a week, and they were out of business 2 weeks later!
Any of you guys have questions about casino's on cruises or daily ships, just ask