As long as you stay within Hellenic waters and as long as you study the navigation charts properly you should be fine. If there is too much wind or the port authorities impose a prohibition of sailing it is in your best interest if you actually stay in the harbour.
We would not like you to use our yacht for racing, unless we agree to it. And we actually do if you want for instance to participate in an organised race such as the Corfu Yacht race, which takes places in October. Neither would we like that you use our yacht for towing another vessels.