Actually, i think there is a good case for closed communion, to ensure it is only those who are of the Body of Christ are partaking, as the Lord's supper is to show His death by that shared communal meal, as per 1Cor. 11.
And ironically it is Caths who claim to believe in the Real Presence that should be excluded from the Lord's Supper, as they usually have never actually been converted, and i speak from experience, praise God now, and contort the Lord's Supper into a form of endocannibalism, supposing to receive spiritual life via physically eating human flesh, though Platonically explained.
I believe one would be hard pressed to show evidence from scripture of the apostles teaching that it is the ekklesia who restricts someone from taking communion. It's always the personal responsibility of the individual as far as I can tell. It's the individual assemblies who allow or disallow fellowship so that would be the only example of "closed communion".
When I was PCA we had a closed communion ... The Pastor would announce that as the elements were being passed
Having had lots of discussion on this issue with conservative Presbyterians, I never found their arguments for closed communion very compelling. Bottom line, it is the Lord's Table and not the Table of Our Regulatory Principle is Stricter than Yours Church.
I found it odd that 1 Corinthians 11 is cited for support of the elders fencing the table by those who hold to closed communion. Paul chastises the Corinthian Church for creating divisions with the meal that is supposed to build unity. Yet when elders temporarily determine the sheep and the goats, aren't they doing the same thing? It might be for good motives but it accomplishes the same thing. Further, when the passage talks of a self-examination (verse 28) and not examination by ecclesiastical authorities.
If I visit a church which practices closed communion, I'll respect their rules and not partake if disallowed and won't create a scene or enter into a great debate but I won't go back.