GET your hair cut! Switch off that mobile phone! Stop chewing gum! Most pupils have found themselves at the end of such an ear-bashing at some point in their school careers.
Imagine, then, the relish with which teenagers Emma Richardson and James Anderson turned the tables at a London conference on pupil democracy.
Delivering a talk to 100 educationists at the British Library, Emma, 15, and James, 16, seized control by asking the audience to stand. Distinguished delegates were then asked to sit down if their hair grew over their collar, if they wore ostentatious jewellery, or if their clothes were unacceptable in the youngsters' eyes.
In the end, by all accounts, only a few were left standing. This emphasised, said Emma ad James, how frustrating it can be when school rules are simply imposed on young people.
To the amusement of the audience, one of those who reportedly fell foul of the teenagers' rules was none other than Professor Bernard Crick - former tutor of Education Secretary David Blunkett and the man who has led calls for compulsory citizenship lessons. He had to sit down because his mobile phone was switched on.
Emma and James, who both attend schools in Northumberland, were speaking on behalf of the organisation Article 12.
It campaigns for recognition of Article 12 of the UN convention on children's rights. This calls for authorities to take the views of children into account when taking decisions that affect them.