5. As the Motu Proprio declares in no. 5 c) the excommunication latae sententiae for schism regards those who "adhere formally" to the said schismatic movement. Even if the question of the exact import of the notion of "formal adherence to the schism" would be a matter for the Congregation for the Doctrine of the Faith, it seems to this pontifical Council that such formal adherence would have to imply two complementary elements:
a) one of internal nature, consisting in a free and informed agreement with the substance of the schism, in other words, in the choice made in such a way of the followers of Archbishop Lefebvre which puts such an option above obedience to the Pope (at the root of this attitude there will usually be positions contrary to the magisterium of the Church),
b) the other of an external character, consisting in the externalising of this option, the most manifest sign of which will be the exclusive participation in Lefebvrian "ecclesial" acts, without taking part in the acts of the Catholic Church (one is dealing however with a sign that is not univocal, since there is the possibility that a member of the faithful may take part in the liturgical functions of the followers of Lefebvre but without going along with their schismatic spirit).
I've already proven a thousand times the motu proprio is wrong--and violates the Pope's own canon law. It is manifestly unjust, period. I have no doubt at all about this. The Pope's argument simply is not credible. It denies the evidence and accuses innocent men of denying his papacy when in fact they acted to protect the Traditional faith from destruction. Besides, he's stepped away from his extreme view since. He now acknowledges Catholics may attend SSPX Masses to fulfill their Sunday obligation. I've posted the letter from his commission stating this many times--but you, like your buddies who like to toss around the "schism" charge, seem to enjoy being spiteful more than being truthful.