I will wrassle some more with closed communion. We do think it's kind of like sex before marriage, sort of, in a way, more or less because it's not just, as it were, vertical - believer and Jesus, but horizontal - believer and the rest of us. But let me think about it some.
Looky here: I know an ex-Lutheran - who is now who knows what, who told me with some kind of pride that his dad swung an altar candle-stick into the belly of a priest who told him (NOT during a service, before it) that the Catholic Church practices closed communion. There certainly is an appearance here of, "You are superstitious scoundrels for saying what you say about the Eucharist AND you deserve a beating for not letting me share in this worthless thing." I think that needs examining.
The natural man cannot know what another man is thinking. (I Cor 2) And certainly a doctrine cannot know what a man is thinking.
But God knows the heart of the man.
And the risk is the same to those on the include list as they are to those on the exclude list.
So if I were writing your rules (and be glad I'm not) - I'd say the priest ought always first explain the perils involved but then, exclude no one. Emphasis mine.
For he that eateth and drinketh unworthily, eateth and drinketh damnation to himself, not discerning the Lord's body.
For this cause many [are] weak and sickly among you, and many sleep. - I Cor 11:28-30