When these kids take summer school, most, if not all, have a summer job on campus. They work at camps. Also, many large universities stay open and have a summer session. ACC programs have the kids living in athletic dorm, so ac is not an issue.
Staying back, or taking a Post Grad year is common practice and the ivies have been doing this for decades. The service academies do the same things. This is because many public school academic programs stink. And this does not matter which district they come from. I went to public school on LI and then transferred to a Prep school. I almost failed out the first year because my public school teachers and the curriculum stunk.
