"At least some bike shops send their personnel to bike school. I just sent one person. I may send another this summer. I obviously think it is worth the couple of grand it cost me to do that (one week only: salary, lodging, tuition)."

Not many do. If you have an inexperienced guy, why not. If I could take a $50 test and get certified I would, I am not spending a week, doing rote adjustment of headsets and hubs to take a test. I spent a year in tech school(3.8gpa) worked as an equipment mechanic for ten years and as bike mechanic for three, back to equipment for three, and now back to bikes for four so far(At the only place that ever kept track my repair rate was 99.6%). The only thing we don't do is major frame repair, i.e. tube replacement. My rep is good enough that a former world champ interupted my dinner( I can't make it through a meal even at home) tonight to drop off his Record Prince because he dosen't want any one else to touch it. That is enough certification for me.