When I was in basic training in the US Air Force towards the end of the 1980s, anyone who wanted out was released without much fuss.
We had a few fellows who decided they’d made a mistake in joining up. They talked to the training instructor in charge of our flight. After a couple of days to get the paperwork done, they were gone - on their way home.
We did have one fellow, though, who straight up threw a fit and demanded to be sent home at once. I don’t know what all went on after he was taken out of our dorm, but I do know he spent most of the following month in a small room attached to the orderly room in the squadron headquarters.
When the other guys were released, they were gone and no longer part of our flight.
The guy who threw a fit remained a part of our flight, and had to be accounted for at every roll call or other function that dealt with trainees by name.
As I remember, he was sent home about the time our flight graduated from basic training.
We had another fellow who had some skill or ability that the Air Force wanted. Smart fella, unfortunately built like an egg or a pear.
He failed the confidence course (what the Army calls an obstacle course) and was moved into our flight (we had started a few days after his original flight) to re-take the confidence course.
He failed it again. And again.
We saw him several times over the next week. Each time carrying his duffle bag to the dorm of a different flight.
I know he eventually graduated, but I don’t know how many times he repeated the confidence course before he made it through.