I think that is just CRAZY. I didn't use my own photographer for budget reasons, but if I would've, that would be COMPLETELY unacceptable. And I would not have taken to any threats well at all (would probably be in a Jamaican jail!). I'm surprised they went to those lengths, it's really petty. That is definitely not a good way to do business. If they take all things into consideration, the few dollars that they aren't getting for the photographer doesn't compare to the money they'll lose if people don't come there at all.
I don't know if the Jamaican Tourist Board or council can have any impact, but I would definitely report these incidents to them and let them know that people are being threatened and physically removed from the property. I would also have someone with a legal background call or write to Riu's corporate office and let them know what is going on and explain the possible amounts of business to be lost when every wedding, travel and tourism board/site is told about these ridiculous practices---as well as the legal impact on the resort if any physical harm actually occurred.
Not cool at all!!!! I'm pissed just hearing about it.