Implicit faith is absurd because it denies human free will. It says that we, as human beings, are incapable of making any "deliberate, conscious choices" to believe or not to believe in certain propositions. It is equivalent to saying that even though I am explicitly married to my beloved wife whom I exchanged marital vows with that I am, in fact, not actually married to her but am implicitly married to another, yet as unknown, woman whom I have never met, but someday, in the afterlife, we will meet. Implicit faith is a form of Calvinistic predestination; its says that no one can choose Hell, all must choose Heaven. This idea is fundamentally wrong, because it contradicts both Catholic Scripture and Tradition. Christ's own words say the following:
"He that believeth and is baptized, shall be saved: but he that believeth not shall be condemned." (Mark 16:16)
Note the conjunction 'and' -- to merely believe is not enough; one must also be baptized. The Council of Trent made this fact clear:
Pope Paul III, Council of Trent, Session 6, Chapter 4, ex cathedra: "In these words there is suggested a description of the justification of the impious, how there is a transition from that state in which a person is born as a child of the first Adam to the state of grace and of adoption as sons of God through the second Adam, Jesus Christ our savior; indeed, this transition, once the gospel has been promulgated, cannot take place without the laver of regeneration or a desire for it, as it is written: Unless a man is born again of water and the Holy Spirit, he cannot enter the kingdom of God (John 3:5)."
The Roman Catechism, a product of the Council of Trent, clarified, exactly, what the Council meant by the word "desire" (votum in the orginal Latin) stating,
Roman Catechism -- Ordinarily They Are Not Baptised At Once
"On adults, however, the Church has not been accustomed to confer the Sacrament of Baptism at once, but has ordained that it be deferred for a certain time. The delay is not attended with the same danger as in the case of infants, which we have already mentioned; should any unforeseen accident make it impossible for adults to be washed in the salutary waters, their intention and determination to receive Baptism and their repentance for past sins, will avail them to grace and righteousness."
Of course, with the One and Triune God, "nothing is impossible," so we can have confidence that those who truly desire Baptism will receive that Sacrament, perhaps in their infancy, or even perhaps via miraculous means.