Responsa do Lamentacje Jeremiasza 3:37

They responded: "Who is this who has spoken that which God has not commanded?" (Eicha 3:37) The final hand-washing is an act of sanctity, and as with all acts of sanctity, Heaven is lenient with the lifespan of those who are lenient in this regard. This is what they truly responded.^*See Tur Orach Chaim 181 and Raavad on Mishneh Torah Blessings 6:2 who quote Gaonim that insist on a final hand-washing with a blessing.