I imagine the origional poster is being paid to do his job. If he is a a member of classroom teaching staff then it isn't by the hour. As music teachers we expect that our job will involve taking part in concerts and shows. Our colleagues in other subjects have other burdens (such as much more frequent marking) - the after school activity thing is simply expected as part of the job. I've done shows with up to 4 performances on consecutive nights - I was not paid and neither were the students or other staf who took part (no peris on those ocassions). I certainly hope the poster will not be one of those music teachers who baulks at after school commitments - it would put him the tiniest of minorities.