I've had good luck with saying anything but "hello." Evidently the robocalls are keying on that word. My current way to answer unknown numbers is "You'd better be someone I want to talk to!" Its wonderful. No scam message yapping about my car's expiring warranty, no free vacations from some resort I've never been to, no calls from "VisaMastercard services." Just silence and a soft "click" as they hang up,