The violinist stood on a makeshift stage under a weathered vinyl canopy hastily erected outside Newark Liberty International Airport in the taxicab holding area. The audience watched him in awe, about 50 drivers in three rows, their yellow cabs a few feet behind, some lined up neatly, others askew. "It was so pleasing to see people dancing -- that never happens," said Mr. Quint, a Grammy-nominated classical violinist. "These people, they work so hard, I doubt they get a chance to get out to Carnegie Hall or Lincoln Center." So Mr. Quint took Carnegie Hall to them, in a miniconcert that was his way of expressing a simple sentiment: Thank you. On April 21, Mr. Quint accidentally left a Stradivarius violin, valued at $4 million, in the back seat of a cab that he took from the airport to Manhattan on his return from a performance in Dallas.
