I stand by what I said. Not only does it reflect quality upbringing, it also, as I said, may reflect one's attitude to work, study, play lifestyle. If this guy had this kind of attitude at high school, to play instruments and compete in swimming that is, he probably still has that kind of attitude today. It a good quality, isn't it?! I also said he should mention it briefly as it certainly won't be decisive in him getting an interview or the job. It can be a nice topic of conversation during "informal" part of the interview. You know, something like:"So, you used to play piano. I did too. Did you ever play Mozart's Piano Sonata no. 4"? "Well, as a matter of fact, I did"!"Excellent, we should play it together sometimes".C'mon, it can't to him any harm mentioning it in his CV.