On the ignore deal, sometimes I accidentally put people on ignore. It happens when I'm on my iPad and I'm scrolling on the left side of the screen and I accidentally hit ignore. I don't know I did it until I see that I'm ignoring them in a thread. After I notice that I have put them on ignore I go and take them off. I have never put anyone on ignore on purpose.
Maybe they could add a second step on the ignore deal, a conformation where you have to actively say yes or no.