No, they don't. But they know dam well that the sport they received a full ride from is their job, and academics come second. Same thing with a Military commitment. I know, they Army paid off my student loans, and in turn I owed them six years. That's how it goes. Don't sign the contract if you can't stand by the commitment. I am not arguing the right, or wrong. Just arguing the fact that he knew the fine print when he took advantage of the GOV education being provided.
You are correct. I am not sure how that time adds up. The time served is different between the reserves, Nation Guard, and Active Duty. If you are not full time you receive credit for time served, i.e. one weekend a month counts as X amount of credits towards days.