I agree there might be some, but I can’t think of a school where that would be true of the majority of recruits.
Like @Momofthree24 mentions, many state associations don’t allow this. There are typically 4 years of eligibility after entering 9th grade. I suppose it’s possible some private schools in those states aren’t governed by state associations, but that would also mean they don’t compete at the highest athletic level either.
In any case, I agree with you that the coach will have likely encountered something like this.