Devious.

A report has found that some schools send "problem" children home for the day when they know they are being Ofsted inspected.  Oh you really have to be cleverer than that!  A few years ago there was some puzzlement when a local school announced a day trip to Alton Towers, I think it was.  The puzzlement was that those picked to go on the trip were perceived to be the least deserving of a treat -  disruptive kids and "thickos" mainly, but all became clear when the Ofsted inspectors turned up on the day of the trip!