MMR program does not guarantee a flight spot.
I know the other Maritime Academies have NROTC units at them and the whole uniform thing is optional unless you are in one of those programs.
When it comes to senior year, AD package goes in. All of the schools, USMMA, CMA, SUNY, etc, are in the same pool when it comes to applicants.
Not many from the other Maritime Academies actually go active duty, so most of the spots end up getting handed over to USMMA. Even then we have less than 20 going active duty Navy this year. 13 of those are flight spots, 10 SNA, 3 SNFO
I dont know how the other schools work, but here at USMMA you can decline going active duty even if you get selected. Generally it makes a lot of people angry if someone turns down a flight spot (happened last year).
This year one person requested SWO, but turned it down to make big $$$ sailing deep sea.