'I will use my quiet voice on the bus'

The elementary students were especially loud going home today. I made several attempts to quiet them down but these were only temporarily successful. I even stopped the bus once and addressed them as a group, threatening to assign seats if the raucous behavior continued. In the end I identified about a dozen of the worst offenders and as they exited the bus I assigned them ten sentences each. They are to write ‘I will use my quiet voice on the bus.’ Two protested that they were not the ones making all the noise but that is to be expected. The others accepted their assignment without comment. I will get the sentences back from a minority the next day. The others will run the assignment up to twenty or even thirty sentences, as ten more are added each day they are delinquent.