I'm not sure of the details, but the Caymans have a reciprocal reporting arrangement with US tax authorities and financial regulators. That is, if you're an American, you can't really hide money there. What you can do is operate a subsidiary there (and it must have resident employees) that generates reasonable revenues with minimal costs, thus shifting revenue and profits to the Caymans low tax jurisdiction. Which will be reported to the US gov, so you better be complying with the letter of both US and Caymans law. Because of these reporting agreements, if there is activity in the Caymans that is illegal in a person's/company's homeland, it will likely be european or chinese, not the US.