You are in a department store and you witness a parent abusing a small child. Do you continue about your business or tell someone?
Define "abusing." Reacting to child's behavior more harshly than I would, or creating actual physical damage? Physically *hurting* child, I'd try to stop it myself. Emo/psycho *damage* would report ASAP, get pix/vid/audio on iPod if possible, license