Additionally, when there is an exclusivity clause it is unethical and unfair to do moonlighting, even if it is as a freelancer, is unethical and unfair. Obviously, you are hired for certain skills and the organisation is paying you for exclusively using those talents, but then to use that very talent on the sly for some consideration is a dishonest practice. Your explanation will hardly bail you out if found out by your paymaster and hence it is not worth the try at all.