I have heard about the Amish also, but to sure how far they go with their shunning. I can see removing someone from the church if they are really doing something awful, and they refuse to stop. I think the Bible even talks about that, but when someone is cut off, with no association with friends and family, and when being totally isolated from your immediate family, I think it goes way to far. JW's take to the highest levels and many JW's have committed suicide, or tried to over the isolation.
JW's used agains such things a shunning. They said it was NOT the Christian thing to do. They actually said that working with people who had problems was the best way to bring them back into the group. Over the years the leadership changed and they become more controlling. Some prominent leaders of their governing body actually started to question things that were changing, they call the changes "new light?. When one governing body member pointed out that their founder, Charles Russell, said that God's word does not change, and mere mortal men should never try and change his words, he was labeled a trouble maker. He finally left the organization because he felt the organization was fading away from what the Bible actually taught, and that some in charge were making up their own "unique" set of rules and abusing their power. Other leaders were afraid he would start talking to members of the group about his views, so they came up with the current policy of shunning. They basically use the threat of shunning as another controlling method to keep people in line. Many have been removed from the congregation simply because they disagree with some teaching. It's rally pathetic.