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This is my understanding too. I don't think "excommunicated" is exactly the correct term. I believe bishops made rules that Catholics were forbidden to place their children i public schools under pain of mortal sin, so parents who violated that rule were not given the sacraments as they were considered public sinners. This was particularly true in parishes that had a Catholic school that the children could go to. I believe this was typical in most dioceses.

That is probably what happened with my godmother's parents.  It would be very easy to conflate such a situation with "excommunication", even though excommunication is a very precise, specific term, and simply being barred from communion as a manifest public sinner, is not as extreme as excommunication.  Incidentally, such a person would also be unable to receive absolution --- I know everyone here knows this, but if they were just to "confess but not mention it", they would be committing the sin of a bad confession and lack of purpose of amendment. 

The "conservative Novus Ordo" types scream bloody murder if you bring this up --- "how can you know what people confess and what they don't?", "you can't know who confesses this, unless you ask each and every Catholic in the world", and similar protestations of denial that this is a major, major problem --- but that is what happens with people who practice contraception, know of the Church's teaching on it, but do it anyway, go to confession and "just don't bring it up".  I have a pet theory, that this is why relatively few Novus Ordo Catholics don't go to confession --- they don't want to confess it (that would entail a firm purpose of amendment), but they don't want NOT to confess it, perhaps afraid it's a mortal sin, but don't want to turn loose of it, because it makes life so much easier, allows one to live that part of their life on their own terms.  I have to wonder how many of these people give any thought of dying suddenly in a car wreck, or having an unknown brain or vascular aneurysm --- a "thin spot" --- and dying in their sleep.  Modern people gleefully say "dying in your sleep is SO the way to go, that's what I want".  No you don't.  You want notice, you want a priest, you want sacraments, you want the Apostolic Pardon in an explicit fashion.  We don't get to choose whether we will die in our sleep or not, but it's not something we should want or wish for.  I know I don't. 

My son is staying with his grandma the next few nights over at the bungalow ---not only is this good for safety reasons, but I think it is helping both of them to find closure over my father's passing --- and we had homeschool classes over there this evening.  I was able to dig out my Woywod/Smith, that is over there with about half of my books, and here's what I found WRT Catholic schooling.  Excommunication is not mentioned.

My son is staying with his grandma the next few nights over at the bungalow ---not only is this good for safety reasons, but I think it is helping both of them to find closure over my father's passing --- and we had homeschool classes over there this evening.  I was able to dig out my Woywod/Smith, that is over there with about half of my books, and here's what I found WRT Catholic schooling.  Excommunication is not mentioned.

I found it kind of curious, that Woywod/Smith would have referred to "other Christian Churches", for it was my understanding, that traditionally, we did not use the word "Church", least of all capitalized, to refer to Protestant sects.

We probably have a gun to our heads, figuratively speaking, in a pluralistic society where all religions are not only tolerated, but where pluralism is seen as a good thing, to make colloquial use of the word "church" (no capital S, if possible to avoid it) when referring to other putatively Christian religious permutations.  Someone such as a contractor (writing invoices, etc.), secretary, attorney, et al, would more or less have to.