Jason,
The ROTC scholarships the military hands out are part of a contract. They are money the students have earned, just as much as anyone who accepts a signing bonus has earned that money. Wages need not be payed at the same time they are earned. True, most compensation is earned within the pay period for which it is payed, but there is nothing wrong with things like signing bonuses (advance pay obliging you to work for the employer for a specific period of time) or pensions (deferred compensation taken in lieu of higher pay, so the individual doesn’t have to worry about saving for retirement). Every graduate of the ROTC program is obliged to at least four years of active duty service upon graduation, with certain specialties having obligations of eight years or more. By the way, if you’re going to spell out an acronym, get the name right! It’s Reserve Officer Training Corps.

Full disclosure, I am a Midshipman in the Naval Reserve Officer Training Corps, Wolverine Battalion (University of Michigan).