In exceptional circumstances a consistory can invite to the pulpit someone who does not necessarily have access to all the pulpits of the federation. Let me give another example: this past Summer the church of which I am joyfully blessed to be a member, Providence Church in Hamilton, invited to preach a candidate who was not from our churches, had not been trained at CRTS, and had not been examined and approved by one of our classes. By a strict reading of the Church Order he was not authorized to preach on one of our pulpits. Only men trained at CRTS have access, and only after having been examined by one of our classes. This man had not met (any of) those conditions. Was it right for the Providence elders to invite him? Yes. He had been trained at a seminary we trust and examined by a classis belonging to a federation we trust. In the circumstances (we are vacant) it was the right thing to do. It is about confidence. (And BTW, he was invited to preach at a number of CanRC churches.)
Similarly, for the Blessings elders to invite Pastor Percy to preach his farewell sermon to his congregation in a Blessings-called service was the right thing to do. The elders had come to know and trust him. By a strict reading of the Church Order he did not have access to our pulpits, but the consistory could make this exception considering the circumstances. This does not mean that Pastor Percy now had access to all our pulpits or that the congregation should be confused by this. Or that the consistory ought to be reprimanded for allowing a man to preach who had not signed our Form of Subscription. It was the right thing to do in the circumstance. The consistory had confidence in him, and the congregation has confidence in their elders.