A lot of this also comes down to your familiarity with the instrument and the genre. I know guitars and drums. I can tell if someone playing a guitar is merely

A lot of this also comes down to your familiarity with the instrument and the genre. I know guitars and drums. I can tell if someone playing a guitar is merely good or world class. However, my exposure to classical music is so little that I have no way of telling if someone is just good or truly spectacular. Reckon the same applies to the average person - most have very little exposure to classical music and can’t tell how good a violinist really is. Would be interesting to see this experiment repeated with a more popular instrument and genre - say, an electric guitar and rock.