Article 5The emphasis on "membership" in the quote is mine, to show it is used in the norms and to give context. But "membership" is a peculiar creature, and in the US, it multiplies entities over and above "registration", which is itself something unique to the US. According to the Canon Law Made Easy site,§1. The lay faithful originally of the Anglican tradition who wish to belong to the Ordinariate, after having made their Profession of Faith and received the Sacraments of Initiation, with due regard for Canon 845, are to be entered in the apposite register of the Ordinariate. Those who have received all of the Sacraments of Initiation outside the Ordinariate are not ordinarily eligible for membership, unless they are members of a family belonging to the Ordinariate.
§2. A person who has been baptized in the Catholic Church but who has not completed the Sacraments of Initiation, and subsequently returns to the faith and practice of the Church as a result of the evangelizing mission of the Ordinariate, may be admitted to membership in the Ordinariate and receive the Sacrament of Confirmation or the Sacrament of the Eucharist or both.
It may come as a surprise, therefore, that parish registration is nowhere mentioned in the Code of Canon Law, and may very well be simply an American invention.At least as we see them here, both the terms "originally of the Anglican tradition" and "members of a family" are completely vague. The Anglican Use Pastoral Provision defines "Anglican tradition" differently from the de facto policy of the OCSP, which includes the Charismatic Episcopal Church as a denomination eligible for ordaining "Anglican" priests, while the Pastoral Provision does not. Clearly the OCSP counts very brief associations with an Anglican denomination as qualifying, when these associations may have been too brief to qualify individuals for canonical membership in a parish in that denomination -- this was the case with the former Presbyterian pastor Fr Baaten, who was in the ACNA for only a few months. Nor, for that matter, was this his "original" tradition.
Thus it's a puzzle that Our Lady of the Atonement made an effort, not only to get parishioners to sign up for "membership" when the parish first transferred to the OCSP, but renewed this effort when the results of the first campaign came up short. Why? I can think of two possibilities.
One, whose strength is hard to gauge, might be that Anglican parishes, coming from a "reformed" or congregational tradition, stress "membership". Up to the 1960s, congregational Protestants had to be "members" of a parish to receive communion, usually the only sacrament for which baptized adults were eligible in any case. After "open table" made all baptized people eligible for communion, this ceased to be an issue. However, because such congregational Protestants were also members of the parish corporation, this also entitled them to vote on parish matters.
But Catholic parish governance doesn't treat all parishioners as legal members of the corporation, and eligibility for the sacraments canonically depends on one's territorial parish, partly independent of registration or the normally nonexistent term "membership". Maybe, though, this was inserted as a way to make these Protestants feel somehow comfortable -- but think about the very real issue Abp Garcia-Siller raised, that these former Protestants could also get the impression thy're not just unique, but separate. That Catholic stuff doesn't apply to me, after all, I'm a member of something better.
A second possibility is political, and perhaps an accounting device: to limit "membership" in the OCSP could be a way to reassure diocesan bishops that nobody's poaching cradle Catholics -- but frankly, I'd be suspicious, considering how vague the terms "Anglican" and "family" are in the norms. I wonder if this was behind the Bishop of St Petersburg's resistance to a Tampa OCSP group. There may be something like an accounting basis: as far as I'm aware, banks still assign every account a branch identifier, despite decades of mergers and the advent of direct deposit and online transactions. Houston and the CDF seem to use "membership" numbers as a way to gauge communities' relative success, or the relative success of each ordinariate.
But the definitions are clearly so vague as to have little meaning. If I started out as a Baptist but went denomination-hopping for whatever reason, but while I lived in Podunk I went to First Methodist before I moved to Second Presbyterian, does that qualify me? Probably. Does it matter? If I've made up my mind to be Catholic and have been properly catechized and received, I don't see how -- but frankly, wouldn't I be better off at a diocesan parish no matter what? Would Fr Bartus and Bp Lopes prefer to have me in the OCSP? Absolutely, they need every last guy who remotely qualifies. It's a numbers game that justifies their jobs.
There's an awful lot here that doesn't add up, and the cure of souls seems to be somewhere far back on the list of priorities.