Absolutely is is a very effective weapon.
Below is a post, I believe by Marvin Shilmer, which exposes that beautifully.
Powerful Weapon?
Heres a quotation for you from Insight on the Scriptures Volume 1 page 787 under the subject Expelling:
One who was cast out as wicked, cut off entirely, would be considered worthy of death, though the Jews might not have the authority to execute such a one. Nevertheless, the form of cutting off they did employ was a very powerful weapon in the Jewish community. Jesus foretold that his followers would be expelled from the synagogues. (Joh 16:2) Fear of being expelled, or unchurched, kept some of the Jews, even the rulers, from confessing Jesus. (Joh 9:22, ftn; Joh 12:42) An example of such action by the synagogue was the case of the healed blind man who spoke favorably of Jesus.Joh 9:34. [Underlining added]
The Watchtower characterizes the form of shunning practiced by JWs as a death-dealing blow. The Watchtower of 2/1 1960 page 80:
So also today, the New World society of Jehovahs witnesses can not and will not tolerate juvenile delinquency to exist in its midst. So, to avoid a possible death-dealing blow by being disfellowshiped from the congregation, wise theocratic children give heed to and follow what Gods Word says: Children, be obedient to your parents in union with the Lord, for this is righteous. You children, be obedient to your parents in everything [this leaves nothing out], for this is well-pleasing in the Lord. Listen to your father who caused your birth, the Proverb says, and do not despise your mother just because she has grown old.Eph. 6:1; Col. 3:20; Prov. 23:22. [Underlining added]
Of WTS shunning of immediate family members, The Watchtower of 11/15 1952 page 703:
The law of the land and Gods law through Christ forbid us to kill apostates, even though they be members of our own flesh-and-blood family relationship. However, Gods law requires us to recognize their being disfellowshiped from his congregation, and this despite the fact that the law of the land in which we live requires us under some natural obligation to live with and have dealings with such apostates under the same roof.
Of WTS shunning of immediate family members living outside the home, the Kingdom Ministry of 8/2002 on page 4 repeats language from The Watchtower of 4/15 1988 by saying:
It might be possible to have almost no contact at all with the relative. [Underlining added]
So, whos using the Pharisaic very powerful weapon today, the kind that could keep people from confessing Jesus out of FEAR?
yesid (for Marvin)