Great information, AuldSoul and Blondie!
The JW baptismal rite is indeed a control issue, because it's the rite that formally joins a newbie to the cult. The vows are most certainly a means for the Society to protect itself legally from lawsuits about disfellowshipping, because when a person voluntarily vows to obey cult leaders, he cannot legally claim that he did not know what he was doing. Ray Franz covers this in his books.
AlanF