Why do people say "their" when the antecedent is singular? Why not say "his or hers" or "he or she?" Laziness I call it. Maybe one day this illiterate expression will be acceptable, as "normalcy" has become. President Harding, not our most literate head of state, used "normalcy" instead of "normality." So it was deemed acceptable. Let's hope that "refudiate" doesn't follow the same path.