In the Reformed view, baptism does not normally convey spiritual benefits apart from the preaching and reception of the gospel. Rather, it increases our understanding of the preached Word; it nourishes and sustains us in our faith; and it confirms the benefits that come through saving faith in the preached Word. Reformed theology’s emphasis on God’s sovereignty and freedom leaves room for the sacraments to work in unexpected ways, but Scripture establishes the norm that the sacraments work in conjunction with the preaching of the Word. (p4)If baptism works "in conjunction with the preaching of the Word" then it would seem clear that baptising those who have not yet heard, understood and received that word is a grave mistake. In Pratt's presentation of baptism as a sacrament I find little to disagree with, it is not magic, it cannot truly operate apart from faith.
However a definition of church such as Calvin's leaves us dangerously open to a church where the clergy are more essential than Christ. Under this scheme without a heirachy approved minister to preach the word and properly administer the sacraments no true church is possible. And so the church as purveyor of spiritual goods and services and the privileged spiritual position of the clergy is maintained, and the reformation remains only half baked.