Perfectly reasonably, some Catholics wonder if all these incoming ex-Anglicans, particularly those joining the Church through Anglicanorum Coetibus, willl need to "change their mind" on a number of key teachings, such as Transubstantiation, the Assumption, the Immaculate Conception and Papal Infallibility.
In fact, the kind of Anglican most often likely to avail himself or herself of the generous provisions of Anglicanorum Coetibus will have come from an Anglican parish where the Assumption and the Immaculate Conception were celebrated with some solemnity, where belief in the Real Presence was taught and held, where the Holy Father was prayed for by name, and where at least some had an appreciation of what Papal infallibility did and did not mean.
For us ex-Anglicans, there are things to learn and things to get used to, most certainly, but there is no need for anyone to be worried that ex-Anglicans arriving in the Church through Anglicanorum Coetibus are somehow going to consitute a separate pocket of half-measure Catholics. What is happening is that these people are coming into the full communion of the Catholic Church, they are coming into communion with the Successor of St Peter: while preparation is required, they are not learning a totally unfamiliar faith.
Even if these ex-Anglicans, like their now fellow Catholics, know what an Ex Cathedra teaching is, there cannot be many who have ever seen it happen. The only example since the solemn definition in 1870 of the dogma of Papal Infallibility in the First Vatican Council's Pastor Aeternus is Pope Pius XII's declaration, in the Apostolic Constitution Munificentissimus Deus, on 1 November 1950 that the Virgin Mary "having completed the course of her earthly life, was assumed body and soul into heavenly glory."
So that more of all of us have seen it happen, here is some truly remarkable footage of that great day in 1950. Pope Pius XII emerges on the sedia gestatoria just before 3.30, and makes his Ex Cathedra declaration at 6.05. Assumpta est Maria in caelum: gaudent Angeli, laudantes benedicunt Dominum : and don't worry, the ex-Anglicans rejoice too.