Can I show up at a Catholic Church & just join the congregaton? What's to stop me?

Yes many are and traditionally have been. All the churches I’m familiar with here are, but I believe some churches in urban areas where theft could be a problem do lock up. The idea is that God’s always there and available if you want to pray.

For the most part, they are assigned geographically in the US as well ( although not it’s not as strict as when I was a kid, it’s still the default even in places where there may be 12 parishes within a 10 minute drive). In my experience, registration is only required if you want the parish to take official notice of you -you want your child baptized, you want to become a Eucharistic minister , you want to receive donation envelopes in the mail , you want to receive the parishioner tuition rate ,etc. It my experience,it involves going to the rectory and filling out a form that basically says “I’ve moved into your jurisdiction” or “I want to be under your jurisdiction”. It does not involve you telling anyone how much you are going to contribute, and you don’t need to register to attend Mass or join various organizations. You don’t necessarily have to register in advance (I registered with one parish when I made arrangements for a baptism) but advance registration may be necessary if you want to arrange a baptism or a wedding in other than your geographic parish.

I’ve acted as Eucharistic minister in Spain and Italy: the priests asked for confirmed people, I volunteered. To act as a reader in Spain, I just volunteered when one was requested before Mass (and if we’re in Mom’s parish, any members of my family who do not wish to read need to be able to claim duress). The Augustines wanted proof of Baptism and Confirmation before I could read in the Spanish-language Mass - dude, just give me the book, I can even pronounce Eclesiastés without stumbling! I didn’t bother trying with the North Miami fellows, the priest wanted me to register as soon as he identified me as “new here”. Since it varied from parish to parish I figured it was a matter of individual policies.

The same Augustines only held Confession by appointment. I took the metrorail to Corpus Christi instead, figuring it would be Jesuits and they wouldn’t have that requirement (it was and they didn’t). For a Church that people on the outside looking in often believe to be monolithic we’re more like sandstone or granite than obsidian, if you know what I mean.

I know what you mean- but just to defend American parishes a bit, I suspect in heavily Catholic countries there’s a lot less outraged “What do you mean I can’t ( be a godparent, receive communion, read at Mass) just because I’m not Catholic?” than there is in the US which I suspect is the reason for requiring proof of Baptism and Confirmation to fill certain roles. I’ve even known nominal Catholics who didn’t understand why their child’s Confirmation sponsor needed to be confirmed his/herself. Possibly less of an issue in Spain and Italy.

It also helps to be registered if you or a family member dies and wants a funeral Mass. I convinced my sister to visit the priest and register so that at her funeral the priest could at least recognize her and have a memory of her.

As i understand it,a Godparent has to promise to see the child is raised Catholic if the parents refuse to, or dies. In such a case why would a non-Catholic want to be a Godparent?

This is true in my experience. In our current parish, we filled out a form that was essentially name and address so they could send us the donation envelopes and newsletter. When my daughter was baptized in this parish, I asked if we needed to submit proof that the godparents were Catholic, and was told by the priest: “Why would you need proof? GOD WILL KNOW.” On the other hand, when I was a godparent at another parish, I had to provide copies of my church records.

In the parish where we lived before this (same city even, just different part of town), there was a much longer form that asked for information about where I was baptized, received first communion, and was confirmed. And even this, I know they didn’t check because I found out later that I mistakingly listed the wrong church for baptism (I listed my childhood parish, but it turns out I was baptized in my grandparent’s parish). So it’s not as if I ever got an investigative phone call. A person who was deliberately trying to fake it could, fairly easily, join up and fill out the paperwork with names of churches chosen at random. I suppose it’s possible that they could do a spot check of every, say, 100 joiners, but based on my experience with many parish offices staffed part time by nice retired lady volunteers who don’t know how to use computers, I would be surprised.

I remember hearing about a person who wanted to be a godparent (this goes to monavis’s question) and did some research to find a parish that had been closed down due to low numbers of Catholics in the area, and merged with a nearby parish (this happens a lot, fyi). So he listed that defunct parish, and when records were requested, eventually received an apologetic note saying that while in theory the old records were transferred to the new parish, unfortunately it has turned out that not everything can be located now, especially for older records. He was able to then say to the baby’s parish “well gosh, not my fault my church lost my records.”

And you have to be confirmed to be a godparent, so I think a lot of people from Catholic families who maybe weren’t that into it, and gradually didn’t really stick with religious education and ended up never being confirmed suddenly realize they want very much to be a godparent when there’s an actual, adorable little niece or nephew in the picture. Even though, obviously, there’s a very specific theological meaning happening for the church, for many people, it’s just more of an “awww, cute baby!” symbolic thing. And then they are surprised when the Church won’t let them.

I am betting a lot of it comes down to the personalities of the people in charge at the parish, and how much office support they have to be running down documents.

Some people just see it as an honor, others think the godparents raise the baby if the parents die and some people don’t see much/any difference between various Christian groups and therefore figure that a Methodist can be a godparent at a Catholic baptism ( and yes the Methodist can be a “Christian witness”, but there must also be a Catholic godparent)

Yes, please. Even Catholics who aren’t in good standing shouldn’t receive, so have the respect not to unless you are in one of the churches that is in communion with the Roman Catholic Church.

Around Christmas and Easter, of course a lot of non-Catholics or Catholics not in good standing will attend Mass. One year our priest did say something about those in good standing when instructing us on how the lines would be formed. But no, you won’t be policed.
<<For Catholics
As Catholics, we fully participate in the celebration of the Eucharist when we receive Holy Communion. We are encouraged to receive Communion devoutly and frequently. In order to be properly disposed to receive Communion, participants should not be conscious of grave sin and normally should have fasted for one hour. A person who is conscious of grave sin is not to receive the Body and Blood of the Lord without prior sacramental confession except for a grave reason where there is no opportunity for confession. In this case, the person is to be mindful of the obligation to make an act of perfect contrition, including the intention of confessing as soon as possible (canon 916). A frequent reception of the Sacrament of Penance is encouraged for all.

For our fellow Christians
We welcome our fellow Christians to this celebration of the Eucharist as our brothers and sisters. We pray that our common baptism and the action of the Holy Spirit in this Eucharist will draw us closer to one another and begin to dispel the sad divisions which separate us. We pray that these will lessen and finally disappear, in keeping with Christ’s prayer for us “that they may all be one” (Jn 17:21).

Because Catholics believe that the celebration of the Eucharist is a sign of the reality of the oneness of faith, life, and worship, members of those churches with whom we are not yet fully united are ordinarily not admitted to Holy Communion. Eucharistic sharing in exceptional circumstances by other Christians requires permission according to the directives of the diocesan bishop and the provisions of canon law (canon 844 § 4). Members of the Orthodox Churches, the Assyrian Church of the East, and the Polish National Catholic Church are urged to respect the discipline of their own Churches. According to Roman Catholic discipline, the Code of Canon Law does not object to the reception of communion by Christians of these Churches (canon 844 § 3).
For those not receiving Holy Communion
All who are not receiving Holy Communion are encouraged to express in their hearts a prayerful desire for unity with the Lord Jesus and with one another.
For non-Christians
We also welcome to this celebration those who do not share our faith in Jesus Christ. While we cannot admit them to Holy Communion, we ask them to offer their prayers for the peace and the unity of the human family.
>>

http://old.usccb.org/liturgy/q&a/mass/communion.shtml

I wonder if the apostles were baptized Christian, and if they went to Confession before hand? I personally don’t go for the communion bread and wine, I have no desire for it. at one funeral the son of the deceased said I was bad because I wasn’t Christian. :o)

One of the strange things in some U.S. neighborhoods will be the SEVERAL Catholic churches over a few blocks. Most have shut down now, but 100 years ago, the German Catholics, the Polish Catholics, the Irish Catholics, the Italian Catholics, etc. would need their own church. So you’d get into an immigrant community and you’d go to church by nationality. In the town I grew up in, our Church was a French Catholic church - we only had the one - but the next town over had a German Catholic church. It wasn’t uncommon to switch towns for church depending on where grandma got on the boat.

Non-catholics and indeed non-Christians are always welcome to attend. Non-catholics should not attempt to receive communion although there is no verification (unless the priest or eucharistic minister just happens to know you). Nitpick- one does not “take” communion, one “receives” it.

Jesus knelt and washed their feet and told them if their feet were clean they were all set, so I am assuming that counted for absolution before they partook of the Last Supper.