Keep in mind that your friend with the three year has an additional year to recover and get cleared by DoDMERB. You don't. Good Luck. This is a tough one.
That is an important point. When you as a 4 Yr. Awardee report in the Fall, if you are medically DQ, you cannot sign your Scholarship Cadet Contract, which means your Award is invalidated. No grace period, no waiting. At that point you participate as a non-contracted MSI, and hope for an in-college scholarship Award at the end of your 1st semester, 2nd Semester, etc. Can you pay for college that year without an AROTC scholarship?
Another point: Practically everybody I know who has played Rugby, even as a Club Sport, sustains some sort of injury -- concussion, separated shoulder, broker wrist/arm/leg, severley sprained ankle, torn ACL, broken ribs, broken jaw, broken teeth, etc. For every injury in basketball, wrestling, baseball, etc, there are probably 3 in football, 3 in Lacrosse, and 10 in Rugby. Rugby probably has more injuries per participant than mixed martial arts or motocross.
So, yeah, it's your decision. Weigh the benefits of participating against the risk of losing your scholarship award.
Increasingly in professional sports, the Contracts the athletes sign prohibit them from participating in sports deemed of high risk of injury. One of those is motorcross, another is pick-up basketball games, etc. You might want to consider yourself, at this point in time, contracted to the Army. Though the Army does not have clauses it its contract prohibiting you from participating in high risk sports, you might want to consider that an oversight
, and follow the lead of professional sports teams in protecting their investment in their players' healthy bodies. Or consider buying insurance through Lloyd's of London to pay off in the event you injure youself and invalidate your Contract and Career (well, that is slightly tongue-in-cheek, but the point is you, just like an athlete, have a lot to lose in the event of a serious injury).