Abstract: A translucent panel covers an open side of a frame. A neon sign forming a warning message is disposed within the frame adjacent and facing the panel so as to be visible from the outward facing panel only when the neon sign is illuminated. Stroboscopic lamps are mounted in the frame beneath the neon sign for actuation together with the neon sign in order to attract attention to the warning being displayed through the panel whenever the neon sign is actuated by the closing of a switch conveniently disposed at a teller's cage or station, a cash register, and the like.