From my own personal experience, when I left the JWs, I had first sent a letter informing them of my decision to leave the JWs, and why. A few days after I had sent them off, a couple of elders came to my door, making sure I was the one who actually sent them the letter. After I told them yes it was me, they asked me why, because in their eyes this happened totally out of the blue, you see I was in good standings with the organization.
I brought up the scripture in Deuteronomy 18:15-22, where it talks about false prophets. I told them that my mother became a witness in 1974 on the sole promise that she would once again be reunited with my older sister who had just passed away. My sister was only 5 years old when she died. I said 1975 came and gone, and that it was now 2001, I brought up a few other points as well.
Their only response to me was not to convenience me to stay, but all they said to me was "It's true what you said." That was the last I ever heard from them.
Even if what I said wasn't about 1914, the same holds true. People do leave when the Watchtower does this yo-yo stuff with the dates they have claimed up in the past.