Many years ago, when I was in charge of our local tower, we were fortunate to have a large number of teenage ringers and learners. I had a policy whereby as each one became competent to ring Bob Doubles I taught them how to call a 120. Because they all had to do it (unless for some reason they absolutely refused) no one saw anything unusual in this. The reaction varied, a few followed it up, in particular one young lady was very keen. She has studied the theory and gained practical experience over the years, with the result that she is now the leading conductor in our Association.