It rarely happens because this board meets once. It is not like scholarships, where they continue to meet multiple times.
Additionally, I have never heard of anyone getting booted from Maxwell unless it was medical. The thing with that is you can only miss X days, hence, even if they got booted minute 1, break a leg getting off the van from the airport. The AF cannot turn around orders fast enough to get someone in to meet the reg of missing X days. Big reason why, at least for our DS's det., only those selected do the bag drag and the physical. That means they are the only ones issued ABU's, ~~~ without name tags, only ones that have the 2nd set of blues, only one with a current medical update including shots. It is not as if you just report like you did for ROTC day one. Just to get the required items from sunscreen to brown tees to blue binders takes a few days, and that doesn't include handing in the medical records to go up and down the pipeline for approval. I believe it was in April last yr that our DS did the drag, and he was given 2 weeks prep, it was an everyday thing...drop over name tags to get the name sewn, order new name tags for blues, spend a night writing the last 4 SS number on every piece of clothing, go to the docs, etc., etc., etc. Than pack the bag, drag it to the det, dump it, get SCORED on fulfilling the list, repack it and bring it back home. Det., then must sent these results, along with your physical to Maxwell. Orders are than cut.
They also can't add someone into the next class since classes are done to max out from minute one. That means there is no spot in the next class.
People do leave AFROTC after Maxwell because they realize it isn't the life for them, HOWEVER, they do not separate at Maxwell, they do it when they return to school in the fall. DS's close friend did this. He completed Maxwell in June and knew he wanted out. He submitted his papers in August. He contacted the det when he got home telling them he wanted out (scholarship cadet), they did the wise thing and said take your time and decide, it could just be too raw right now. His actions also had a large fiscal tag of 30k+ because he dropped out of the program, he was not asked to leave.
I would not place any hope that the AF will call anyone up that didn't make the list.
You also need to understand this is a manpower issue. The AF has too many coming down the pipeline and this is a way to save money. If the cadet is on scholarship and doesn't get it, the scholarship is considered void, and that relieves them of 2 yrs of payment, plus the 4 yrs AD. It seems harsh, but the minute you realize that the military operates like a corporation when it comes to budget and personnel, is the minute you realize what is promised always has a loop whole...devil is in the details.