Originally Posted by Swiss Guard
The MP can certainly be interpreted as prohibiting the Tridentine Mass during the Triduum since there can only be one Mass each day, the NO is still the ordinary Mass of the Church, and the Tridentine Mass is not to supplant the NO at a parish that currently offers the NO Mass.
There is nothing whatsoever in the MP which mandates that the ordinary rite take precedence over the extraordinary rite in every territorial or ethnic parish church or shrine. If there is only one Mass on Sunday or Holy Days, it can be of the extraordinary rite. Likewise, the only Masses during the Triduum can use the extraordinary rite. It is up to the pastor of the parish or the rector of the shrine to decide.
There are some "mixed parishes" today under the Indult at which the only Holy Day Mass offered is according to the 1962 Missal. I don't think the MP has the effect of forbidding this current practice.
It may be the case that very few territorial parishes will end up giving precedence to the extraordinary rite for any Sunday, Holy Day, or feast of the Sacred Triduum. But it is not prohibited by Rome.