Answer:
Being a member of a church is not necessary for salvation in baptist doctrine. Therefore, a congregation can not "excommunicate" a member from his relationship with God. A church congregation is a group that tries to foster the beliefs and behaviors of a first century church and in rare cases a person could lose his membership in a church. This only means that voting in business meetings, being on committees, and serving as a teacher in the church would be limited. Three hundred years ago there was also a "shunning" when the church was a central part of a community.
Again, let me emphasize that this doesn't break the bond between a believer and his God nor does it prevent a believer from worshiping.