Echoing it totally depends on the school! But with 30% day students, I have to believe your school has figured out what to do with them, and how to integrate them well.
At my sons’ schools, day students were assigned to a room, so they had a dorm they did things with. At one school, they got a desk in the room, and that was where they studied; at the other school, no desk, but they had a bed for the nights they stayed over. A third school we ruled out because day students were not assigned a dorm, and had no place in the school except a day student locker. So – it varies!