Even on her first day canvassing for signatures, Aubrey Child, like most of her classmates, was a quick study on who to approach, winding up with 20 signatures after two train rides. "If they're on their phone and they weren't listening to the issue, then they probably actually wouldn't care," Child, a 9-year-old with long braided hair, explained with clipboard in hand. "But if they were being attentive and looking at us, then I think they would want to sign our petition."