Unattended pianos in public places are magnetic. Whether it’s an artistically painted piano sitting on a city sidewalk, a standard upright at a school or a grand in a ritzy hotel, the instrument calls to people. In many cases, the people drawn to the keys sadly have little skill, but occasionally someone who clearly knows what they’re doing will show up and answer the siren song of the waiting piano. On Saturday, July 11, it was a small model waiting patiently for a new owner at “ReMARKable Cleanouts,” an antique store and auction house in Norwood, Massachusetts, that grabbed the...