This is an interesting topic for me and feels very conflicted.
I boarded from 8 to 18 and my parents only lived 45 minutes from the school. There were day pupils that had longer journeys in than I had. I guess there were no mitigating circumstances for my parents in mumsnet judgement. I suppose I went for literally the "old school" reason.
However I did and do have a great relationship with my parents. But I think that is due to what one poster wisely before stated that my parents are great people and always very active in taking me out and supportive. Also it was always lovely to be home. And when I was at home it was just for fun and to relax. No homework, no activities , no pressure. I also got an excellent education, brilliant results and it paved the way to an interesting future and, true to cliche, made me very independent.
BUT I know I would never send my children to boarding school.
The reason is the pastoral care. I am quite young and came after the big upgrades in boarding - individual rooms, houseparents, personal tutors, spanking new facilities which were the best that money can buy - but on a day to day level it still is what it always was: your friends are your substitute for a family and you sink or swim with them.
Houseparent/s spend almost all their time on routine tasks - roll calls, food and medicines for the 1 or 2 that are ill, discipline punishments, disputes, stationery, exeat requests, lights out, lock up etc. Personal contact with pupils really has to be brief and is usually surrounded by many other people. The idea (not just for me,but to any of my friends or my friends who went on to other senior schools) that you would tell these people your personal issues let alone embrace them is frankly fucking ludicrous. I'd sooner sit on my manager's knee and discuss my menstrual cycle than open up to a house tutor.
For years I couldn't understand why twice weekly these people would pop in for a brief strained chat about piano practice . But now I realise - ticking the Pastoral care box . Not bad people but the whole scenario simply does not in anyway replicate what you can get from family. And what I did get from my family (in the holidays).
Whew! Always wanted to say that.