I think I did once, based on the idealised version as described by Enid Blyton in her Mallory Towers books, midnight feasts in the dorm and all that.
Having said that the idea of boarding at anything like the convent school I went to, would be the stuff of nightmares, the nuns that taught us were bad enough as day teachers (I use the word teacher loosely) spiteful, full of hang ups, prejudices and generally weird notions. From everything I read about religious boarding schools of yesteryear they sounded awful and some adults talk about their lives having been blighted by such experiences, and those testaments have come from some of the top ones such as Ampleforth.
Nearby me is a boarding school who have thrown open their sporting facilities to the general public if you join as a member, which I have, 25 metre pool, gym, squash courts, indoor gymnasiums for numerous classes, yoga, pilates etc. . The pupils have their own changing rooms, but members often see them come and go they wear a distinctive uniform from a bygone age. They recently asked them I believe, if they wanted to ditch this strange garb, but they didn't. They look happy or rather they don't look unhappy. The pupil intake is very ethnically diverse and the school is known for its charitable ethos it gives out loads of bursaries and scholarships. It appears to be an amazing place composed of umpteen red brick buildings with spires all over the place, my grandchildren, when I've taken them swimming there predictably call it Hogwarts
There is also a sign as we drive in which says "Dead slow children crossing" which sends them into fits of laughter. It's a drive round country lanes to get there, being surrounded by acres of land and playing fields.