Someone has to get the first time surgeons. If you told the patient that their surgeon had never done this before, nobody would take that chance. But then we'd quickly run out of surgeons because the new ones aren't able to learn properly. At some point, someone has to take the chance on a new surgeon, or a pilot on their first trip, or the air traffic controller on his first day. I wonder how often we trust our lives to the (technically) inexperienced.
Mokalus of Borg
PS - I bet it's more often than we think.
PPS - But probably not alarmingly often.