Apparently - it's in the Daily Telegraph today - Mr Cameron thinks it's a good idea for children to stand up when Teacher enters the classroom - and the same when their Parents enter the room.
This simply reveals a truth which ought to be better known, that the English upper classes do not bring up their own children.
In normal, good-enough relations between parents and children, there is not a separate category of Discipline. Children grow up in close proximity to adults who care for them, praise them, chide them, have fun with them, get exasperated with them, cuddle them, share their sadnesses .... In this context, there are undoubtedly prohibitions ("Don't put it in your mouth!) and Rules ("Bedtime!").
But if things are going well between adult and child, there is no netherworld to be dealt with under the heading of Discipline. There is no Waiting Until Your Father Comes Home and no Being Sent To Your Room prior to a decision about your Punishment.
The upper classes do not get this idea since, in large measure they do not bring up their own children, who remain strangers to them. The parents have more important Things to Do. The Queen and Prince Philip did not bring up Prince Charles. He was just another person who had to stand up when his Parents entered the room. When his parents returned from a foreign trip, he stood at the end of the reception line waiting to shake their hands.
In good-enough parent-child relations, most Prohibitions and Rules can, if needed, be given a short explanation and justification.
But in School - and, later, in the Army - we have Prohibitions and Rules for Prohibition&Rules' sake. They cannot really be justified, except by lengthy and contorted argument, and thus can only be imposed. Behind them stands the threat of Punishment which, like Mr Cameron's version of Discipline, is a separate and awful category quite apart from the business of daily living. School Uniform is the paradigm case of this arbitrary world (Pierre Bourdieu would say "cultural arbitrary") of Rules&Discipline.
I recall an extraordinary occasion, which touched me.
From 1988 to 1993, I was Director of secondary teacher training in charge of the University of Sussex PGCE. It was a small course - uneconomically small - and it needed to expand to survive.
Our course had been conceived as a leftish, radical experiment but happened to fit well with rightish, radical ideas being promoted by Mrs Thatcher's governments. Exploiting the ambiguity, and conscious of the need to grow the size of the course, I sought visits from rightish politicians and think-tank policy wonks.
The day came for a Major Visit by the right-wing Baroness Cox, the Baroness Warsi of her day. As part of the encounter, I assembled a dozen of our PGCE students - able graduates in their twenties and thirties for the most part - to meet with her for an hour's discussion. They were already sitting around the seminar table when I came into the room with the Baroness. And they all stood up.
Afterwards, I asked them how this had happened. They had met and discussed beforehand. They knew the course was On Parade, even if not being officially inspected, so they decided among themselves - probably not a Tory among them - to respond to the situation. So they stood up. Bless them.