Semper Fi society does go out to the field and does field training and humping would be a part of that. They do field exercises a few times a semesters. They also host lectures, have social events to meet and mingle with Marines, teach how to conquer the O Course, and try to teach about the history of the Corps. They are trying to teach Mids about the Marine Corps, they won't have Mids doing 20 mile humps at a field exercise. Its mostly to gain exposure and understanding of what is to come if a Mid selects USMC out of USNA. SOT probably does alot the same, but probably alot more PT, especially on the water side. There is a specific stroke that is critical to learning the long swims that those guys do in training, so its important to learn that early. Also being comfortable in the water is critical so the more time in it, the better for them. Its funny my best friend still calls me motivator. I am a civilian and have been for a long time. He is still active duty, former Blue Angel and CO, yet I am the still the motivator to this day.