I don’t think I ever experienced more than two or three, and that was bad enough. Say you’ve got thirty children, thirty watches, spread over five minutes, that’s an average of one every ten seconds.
It was most pupils in my classes. Kids got kudos for having fancier/louder chimes than others. Then came the rush of calculator watches, so everyone started getting watches confiscated before exams, and that other teacher's favourite: the TV Remote watch. Our school admistered masking tape and/or TipEx over the IR receivers to tackle this.
