Church officers in Reformed denominations can be deposed from office. This is a form of church censure. Teachers who are ordained in these denominations do not take such process lightly, nor do the folks in the pew who also happen to support the ministries. It's unlikely that a minister who is deposed, say, for legitimate theological reasons could continue to prosper in that "independent" ministry.
From my experience, students attend seminaries on their own, not because a particular church sends them.
Are you familiar with the way Reformed denominations generally operate wrt seminary and their students? For example, sticking with Westminster Seminary, each applicant must submit a church reference form to be filled out by the leadership which states (in part) "The Admissions Office takes very seriously the evaluation that you will give below. Our primary concern is to admit those who are deemed by their spiritual mentors to be called by God to ministry." Generally seminary students must be "under care" by their respective church body, usually a presbytery or classis. I believe this is the rule in most Reformed seminaries.
The church might recommend a seminary that is close to them theologically, but ultimately it is the student who decides and pays for the education.
Having been a member for many years of my presbytery's theological examination committee, I can tell you that students who do not attend "approved" seminaries have a very hard time making it through the process. The content of the courses they take is carefully inspected, and their examinations tend to be much longer and more intense. A student from the PCA would be advised of the task should they attempt to go off to some unapproved seminary and then try to come back into the PCA as a teaching elder.
Of course it does happen. We get students all the time who attend Dallas Seminary or Fuller Seminary who later "see the light" on Reformed and covenant theology and then wish to come into the PCA. We may give them a hard time, but if they can demonstrate a suitable level of competence in theological matters they can get in.
All of which clearly points to accountability.
I believe BD is limiting such to the direct hiring/firing and control of the financial purse strings. Ours is more deliberative and inferred.
I think we are getting off subject. The question is are the gifts of evangelist, preaching/teaching (Eph. 4:8-13) given by the Holy Spirit as an office to the institutional church or are they given to individuals (like the charisma in 1 Cor. 12:4)?
In other words can an individual have these gifts and operate as an itinerant teacher, evangelist or church planter or are the gifts given by the church "with the laying on of hands (ordination)" and removed by the church as it wills? We are not speaking now of over sight or accountability but the actual gifts themselves, (individual or institutional?).