Steve, it seems to me that Acts 15 flies in the face of our traditional ideas of congregational autonomy. There we have the Jerusalem church stepping in to prevent heresy in the Antiochene churches. Not only that, but one elder, James seems to serve as spokesman for the group and makes the final decision that Paul and co. take back to Antioch.
I see the NT churches as more of a network of churches than several fiercely independent isalnds that have no contact with each other.
How many times have I seen CoCs withdraw fellowship from a church, when the truth is they never had any fellowship with that church to begin with. This happened to my church after we had our first assembly with North Wood United Methodist Church. Several area churches of Christ and several from hundreds of miles away, disfellowshipped us, when we'd never even been in fellowship with a one of them.