In the Catholic Church, the general maxim is (to put it simply) that the Sacraments are binding on us, but they are not binding on Christ (since nothing can limit Him.)
I usually hear this applied to Baptism: it is binding on the believer (in fact, binding on the whole human race) to be baptized. If you realize that Baptism was instituted for your salvation, and that God has commanded it, then you are morally obliged to be baptized (in fact, morally obliged to be received into, and remain within, the Catholic Church!!)
However it is not binding on God. Therefore if He wishes, He can give the grace of baptism wheresoever and to whomsoever He wishes, in any manner He wishes.
Catholics better-educated than I am, help me out and correct me if I'm wrong, but I think the same general maxim applies to the Eucharist. Objectively, if you have the correct minister of the sacrament (a validly ordained Catholic priest) and he does the correct actions ("do the red, read the black") to the correct stuff (wheaten bread and real grape wine) with the correct intention ("I intend what the Catholic Church intends") then and ALWAYS then, it is transubstantiated and becomes the real Body and Blood of Christ. No matter whether the person who receives Communion believes it or not.
Of course the spiritual condition of the recipient will determine whether you receive it unto salvation or unto condemnation: great faith, great love = great blessing. To receive unmindfully and unworthily, not in a state of grace, would bring condemnation. (But in any case, it's still the True Body and Blood, even if the Blessed Sacrament is in the hands of Anton LaVey.)
However God is not limited by this. So -- I think ---if a person who received bread and wine which was not validly consecrated, but desired Christ, this person could still receive His True Presence in some way surpassing our understanding. Just because He, the Lord, is entirely unconstrained and can do whatever He wills.
Amirite?
Sounds good to me.
As an EME I frequently would go to the hospital and pray a spiritual Communion with those who could not receive anything by mouth. I felt a very strong presence of Jesus in the room. He loves us so and so wants to be with us that he bridges whatever differences and flaws we have. We cannot “do the magic” perfectly so we have to rely on Jesus. I say this to those who believe that it has to be a Mass in Latin in exactly a certain form and I have to be wearing a hat and a long skirt. Give me a break. And actually Jesus does just that.