Outside of NCAA rules, D1 in this case, aren't there conference rules as well? For example I remember asking a few years back about the Big 10, and they have specific rules they have to follow outside of the NCAA rules.
My 2022 was recruited by a top ACC school before he stepped foot onto a HS field. Based on the recruiting history of the school he probably would have gotten an offer if he attended their camp. We didn't. The thought process was if he's so good he's getting this offer now, there will still be plenty of offers when he's more mature and has a better idea of what he wants to do.
Fast forward 3 years, he's committed, and a good ball player, but he's not good enough to play for that school. Maybe he would have made it into the fall, but wasn't making it to the spring.