The IHM schools of the communities of Fr.Leonard Feeney, in the dioceses of Worcester and Manchester,USA are teaching the Marchetti error to Catholic school children.With this irrationality they interpret Vatican Council II as a break with the past. LG 16 becomes an exception to the Feeneyite version of extra ecclesiam nulla salus.
The Slaves of the Immaculate Heart of Mary, the religious communities who manage the IHM schools also interpret Vatican Council II (LG 16) as a break with the traditional interpretation of the dogma on exclusive salvation in the Catholic Church.
The fault is not with Lumen Gentium 16.The fault lies with the religious communities and their bishops. The St.Benedict Centers interpret LG 16 as referring to visible cases, instead of invisible for us cases, in the present times.If these cases are invisible for us in 2015, since they are in Heaven, then LG 16 would not be an exception to extra ecclesiam nulla salus. No one in the USA knows any one who will be saved this month, without 'faith and baptism'. So no one knows of an exception to the dogma.No one knows of someone who has gone to Heaven this month or this year, saved in invincible ignorance with or without the baptism of water.Nor will they know any one in future who will be saved as such.
If there was such a case in the past know human would know of it.
We cannot say that St.Emerentiana or some other saint is in Heaven without the baptism of water, since humanly we do not know. We cannot see or know of an exception since we cannot go to Heaven and confirm and return.
If someone in the Church declares there is a person in Heaven without the baptism of water it would be suspect. Since God could have sent a preacher to teach and baptism that person without our knowing it (St. Thomas Aquinas). Or, God would baptise then after they return from the dead only for the baptism of water.(St. Francis Xavier).
So there cannot be any exception in Vatican Council II to the rigorist interpretation of the dogma on salvation.
LG 16 would be referring to a hypothetical possibility for us. They could only be explicit for God.These cases would have to be followed by the baptism of water in the Catholic Church since this is the dogmatic teaching.
With the baptism of desire or without the baptism of desire they are still hypothetical cases for us . So they cannot be relevant or an exception to all needing to become formal members of the Catholic Church, with faith and baptism, to go to Heaven and avoid Hell.