code: protected void clientLoggedOn (String nodeName, ClientInfo clinfo)
      {
          PresentsSession session = _clmgr.getClient(clinfo.username);
          if (session != null) {
              log.info("Booting user that has connected on another node",
                  "username", clinfo.username, "otherNode", nodeName);
              session.endSession();
          }
      }
docs: Called when we hear about a client logging on to another node.