Well, we (that is, myself and my family) have left membership in the OPC and are now adherent members of the FPCS.
The latter was very easy, because the FPCS follows traditional Scottish Presbyterian ways of thinking about membership. They do not engage in any kind of public ritual to receive members into the visible church besides baptism and a general profession of faith. Since we have all been baptized and those of us old enough to do so profess biblical Christianity, we are considered members of the visible church. Because we have acknowledged the oversight of the FPCS and have professed submission to them (and have developed a particular relationship with the FPCS church in Santa Fe, Texas), we qualify as adherents of the FPCS (that is, we are members but have not yet been granted communicant status--that's the next step). You can read about the traditional Scottish Presbyterian way of thinking about membership, baptism, and communion here.
Our removal from the OPC was not so easy. Our OPC session decided that becoming a part of a church that has no local congregation (the nearest is in Texas) is equivalent to leaving the visible church altogether, and so, in asking to have our names removed from OPC membership due to our identifying with the FPCS, they consider us to have engaged in "cutting [ourselves] off from the visible church and relinquishing all rights to be considered Christians" (their words). We regard this position as extremely odd, because in a Reformed and Presbyterian view of the church church membership is regarded as a catholic affair. That is, when you join the church you are joining the whole catholic church, and simply having particular circumstances which cause you to exist distantly from a local congregation does not per se cause you to be outside the visible church. (See, for example, Scottish Presbyterian minister Samuel Hudson's discussion of these matters here and here.) Of course, in most circumstances being near larger bodies of the church and particularly the elders of the church is ideal, for obvious reasons, but this does not imply that there cannot be legitimate circumstances which might involve a more distant relationship--such as necessary and unavoidable circumstances (like being unable at present to move to Texas) or even possibly certain legitimate callings (such as perhaps missionary work) which might warrant living at a greater distance. What is required, of course, is that fellowship with the church be maintained in some way and submission to the elders be retained, but the essence of these do not always require immediate locality. Ideally, in most circumstances, it is best for a single parish to live together in the same neighborhood, and yet, especially in this day and age, other factors sometimes make this either impossible or problematic all things considered. But this day and age also affords opportunity for easier contact even at a distance. In our case, we are able to visit Santa Fe hopefully with some regularity, receive visits, listen to sermons, engage in email and phone conversations, receive the sacraments on occasional visits, etc. And informal fellowship can also be maintained with other local Christians and churches which, though lacking de jure legality, manifest the de facto presence of the Body of Christ (we are now attending New Song Presbyterian, for reasons stated in the next paragraph).
The OPC session has also decided that our speaking to others about presbyterian church government, the implications of denominational division, and which churches possess de jure authority (a sample of such speaking can be found here and in larger form here) constitutes a slanderous charge of sin against the OPC, and thus has forbidden us (unless we should forbear to speak to any others about these things) from continuing to attend the OPC church in Salt Lake. We find this reaction to be overly extreme. Certainly, some of our positions are critical of the OPC, and we do deny it to possess objective legality, but at the same time we also recognize it as a part of the de facto visible church and thus of the Body of Christ. We do not presume to judge the motives of anyone in the OPC with regard to the OPC's continuing to exist separately from the FPCS, though we believe this continued separation to be wrong. We believe that informal Christians fellowship can and should be maintained as opportunity arises. We feel that a less extreme response to us was called for, given that the Reformed world is in a greatly divided state and many groups of Reformed people are at odds on some things with other groups. For example, the RPCNA maintains exclusive psalmody--the position that it is wrong to sing anything other than psalms in public worship. The OPC, on the other hand, allows the singing of hymns. Thus, both sides accuse the other of sin (which is just a word that means "doing something wrong"), and yet they are able to maintain friendly informal fellowship (but not ecclesiastical unity). Even within the OPC, there are prominent persons (such as G. I. Williamson) who maintain the exclusive psalmody position, and yet are able to maintain not only informal fellowship but even membership within the OPC. Many people in the OPC are also able to be on friendly terms with baptists, who affirm that it is wrong to baptize infants, and vice versa. We believe the OPC is wrong in some areas, including in remaining separate from the FPCS, and we believe that it lacks objective legality because of its continued separation, and yet we also maintain that it is a part of the visible Body of Christ where, so far as we can tell with a judgment of charity, salvation is being attained, spiritual gifts are building up the body, gifts of leadership are being used by God in his providence, etc. In short, the people and the work of God go on there, despite its being "schismatic" (that is, unjustly out of communion with the rest of the church and thus lacking such objective legality as would warrant its being joined with in the normal fashion). We thus feel that nuance towards us would be more appropriate considering our nuanced attitude towards the OPC and the ability of others to get along despite what I would consider equally serious disagreements (for example, it is no light thing to neglect to give the covenant sign to one's children as baptists do, or to apply that sign without biblical warrant as baptists believe paedobaptists do). We do not wish to be boisterous or obnoxious in holding our views or speaking to others about them, but simply to have the freedom to discuss them peacefully as opportunity arises (which will almost certainly be very rare within a local congregation--most of my efforts go to writing these blog posts and other forms of broader publication). Surely, then, we are no greater threat to the OPC, even from their point of view, than baptists and other exclusive psalmodists. And, of course, from the point of view of the truth, we are no threat at all, for our position is biblical and Presbyterian.
So there is an oddity in our current situation. One church says we are no longer members of the visible church, and another says we are, and both ignore the position of the other. This is, of course,
precisely the situation that my discussions of presbyterian church government are trying to call
attention to. If the OPC and the FPCS recognize each others' legitimacy
and authority in a presbyterian system, the way forward should be
clear: The OPC session ought to pursue upholding their position through the courts of the church that the OPC and the
FPCS both acknowledge as binding. But, of course, there are no such
courts, because there really isn't any presbyterian unity between the
denominations. Instead, the OPC and the FPCS just ignore each other, as
if they don't attribute legitimacy and authority to each other.
who is right? Are we members of the visible church or not?
Fortunately, our position is that it is the FPCS which has the right to make that judgment, because they have a valid right to separate
existence and thus to de jure legitimacy and authority, while the OPC does not.
For more on the theological issues, see here. I have also written a book on these matters (the theological matters, not the personal situational matters) which I am working to get published at this time. If you have any questions about that, let me know. (The book is now published and can be found here.)
UPDATE 11/3/14: See here for an update on how things are going at New Song PCA.