I posed this same question a few months back in regards to fitness levels for professional and rec divers. While it is true there are no set standards and instructors require students to perform task that they themselves may not be able to perform due to their level of fitness. I have to wonder, as an instructor in charge of students (i am not an instructor) in the event of an emergency what is that instructors duty to act. if there is not a set standard for the instructors duty to act, then I forsee this as a time bomb waiting to explode. What would be the instructors liability in the event of an emergency and he/she was unable to complete a simple swim to get to the student in trouble and a death results.