My use of the term "True Orthodox" does not refer to the canonical Orthodox churches. It refers to those schismatic churches which use this very term (another is "Genuine Orthodox") to assert the notion of their sole custodianship of grace. By separating themselves from their mother church, and by refusing to submit to the obedience of canonically-consecrated bishops, they are therefore "out of the loop", as it were. A current example of such schismatic activity is the appearance of breakaway groups which refuse to recognise the validity of the recent reconciliation between ROCOR and the Moscow Patriarchate. These folks may be sincere, but misguided at best. Deliberate separation such as this is indeed little different from the common protestant approach: "I don't agree with the decision of my church, so I'll set up one of my own."
An inviolable principle of the Orthodox Church is the responsibility of the episcopate, the shepherds and overseers of the Church, to "rightly proclaim the word of Your truth". If a priest proclaims heresy, or is disobedient to his bishop, then his bishop is obliged to correct him. If a bishop does the same, his fellow bishops likewise should move to correct him. It is a conciliar approach. If the errant cleric refuses to change his ways, then there may be cause for defrocking or other serious action.
This might all sound legalistic, but it is not. This conciliar approach is what Christ appointed to His apostles. Conciliar as in "a decision made by a group of people of one mind", rather than by one man by executive fiat. There are any number of scriptural references which attest to this. Numbers have nothing to do with it either. Two historical examples come to mind: the question of the Judaisers in Acts, and the errant teachings on the Holy Trinity of Arius of Alexandria. Both the Judaisers and Arius "had the numbers", but St Paul and the Fathers of the Council of Nicea, notably St Nicholas of Myra, prevailed.
On heresy and the calendar: Heresy is the alteration of God's law. Adopting the Gregorian calendar is not an act of heresy. If it were, then no canonical communion between the NC and OC churches would be possible. An irregularity, an anomaly, yes. Heresy, no, despite what some may try to say.
My understanding is that any church which calls itself Orthodox must be under the jurisdiction of a canonical patriarchate, or, in unusual cases such as the Russian Orthodox Church Abroad (which is now in full communion with the Moscow Patriarchate), be under the jurisdiction of a Synod of Bishops, where the canonicity of the consecration of such bishops is beyond question.
Most, if not all, of these schismatic Orthodox (in Greece and in other countries) have set up their own hierarchies of bishops and, in a few cases, patriarchs, who are not in communion with any of the canonical patriarchates or synods. I find it difficult to believe it is sufficient for a breakaway church to conduct its rites and services in a manner identical to the church from which it cut its ties. The fact remains that such a church is disobedient to any canonical hierarchy, and, to put it briefly, this has enormous practical, doctrinal and sacramental implications.
A good analogy from the West would be the various Roman Catholic groups which have never accepted the decisions of the Second Vatican Council. These churches have their own bishops and pope, and promote themselves as the "true Catholic church", they have branded all the post-Vatican II popes as antichrists, and the established church of Rome as heretical.
Food for thought, folks.