Part (b) (ii) seems to be open for interpretation. A pleasure boat, whether fishing or not, could be restricted in its ability to maneuver. A sailboat has no way of knowing if a power boat is restricted or not. Both vessels are responsible for avoiding a collision.
Might be one of those "lawyer laws" that would be enforced to the max if you are involved in a boating accident, where fines and penalties could be more severe if you haven't had a Boaters Safety course.
I know some charter captains that need a new Boaters Safety course to remind them that they don't have any more right to be on the lake than the non charter boats.