Since the typical recreational boater can't tell the difference between
day shapes for "RAM", "Not Under Command", and "Mistress stay away the
wife is onboard". It is generally best for them to assume they are the
give way vessel. Particularly with regards to craft which are larger
and/or may have more difficulty in manuvering. It may be that this
particular Whale Watch boat was bending the rules. But if he had used
sound signal to indicate that he intended to leave you on his Starboard
Side. Would the OP have recognized it and known what to do. Would the
average recreational boater have known what to do?