Detention without notice - a good idea?

I was watching David Cameron doing a public Q+A session a week or so ago. In response to a question from a teacher he began to explain what the coalition was going to do to help teachers improve pupil behaviour in schools. One of the ideas he pushed quite strongly was to give teachers the legal right to detail pupils without notice. Good soundbite: let's get tough on the little blighters, show 'em who's boss, eh?

But how many schools would actually make use of the legal right to detain without notice? There are good reasons why schools give parents 24 hours notice; and those reasons don't go away if you remove the requirement for notice. Detaining children after school without notice would do nothing other than damage the relationship between schools and parents. Many pupils have familial responsibilities outside school time, from collecting younger siblings to doing shopping on the way home. They may also have appointments with a dentist or doctor. How thrilled would you be if your family visit to see Gran in hospital was kiboshed by little Johnny being an hour late home from school, no note no explanation?

It's simply not worth it for schools to implement a no-notice after school detention; it would undo much of the work schools do to build a positive, supportive relationships with parents. So thanks, Dave, but you've offered us a bit of a chocolate teapot there, mate.