Yes, the Church of Scientology goes too far to retain members, because a lot of members give some pretty vivid accounts of scary things that happen to them when they try to quit. If a person wants to quit, they should be allowed to do so at any time. They should feel ostracized or threatened just for changing their opinion.
The church of Scientology has a history of using mind control techniques and mentally manipulative tactics, as well as engaging fear in church members, to keep them in their church. They use their unique testing methods to convince members that somethign is "wrong," with them and the only way to cure it is to stay in the church and follow their programs. Of course, this all comes at a high financial price.
From some of the things I have heard about the Church of Scientology it sounds more like a cult than a religion. Trying to get out of this religion is a difficult feat that echoes that of a cult. Members of this church also have to buy their way to a certain status. This is not a real religion folks.
Church of Scientology has a policy of Attack the Attacker. They attack anyone who criticize them in a public forum. They retaliate in the form of lawsuits and public counter-accusations of personal wrongdoing. Many of Scientology's critics have also reported they were subject to threats and harassment in their private lives.