'Local convenience stores had problems with teenagers "hanging out" in their parking lots. The stores wanted teens' business, but not the fights and drug-dealing that sometimes accompany late-night loitering. An influence expert recommended that store owners purchase several samples of a certain kind of music, and play that music through loudspeakers in the parking lot. Upon hearing the music, the teenagers voluntarily left--and stayed away from--the parking lot. The music did not affect sales to teenagers, however, as music was not played inside the stores.'