That depends on how you mean it. Please let me explain.
If one thinks of registration as meaning “I am a member here / I am a parishioner here” then it is a problem.
On the other hand, if one thinks of registration as being things like: being on the parish mailing list, having donations recorded, being involved in social activities, and things like those, then it’s fine.
The best way I can explain it is like this:
According to your profile, you live in Maryland.
What state considers you a citizen of that state? Seriously, which one? Can you live in Maryland but consider yourself a citizen of, let’s say, Virginia or Pennsylvania? What if you live closer to Harrisburg than you do to Annapolis? Does that mean that even though you live in Maryland, but the other capitol is closer you’re actually a citizen of that other state? Maybe you do, and there’s nothing wrong with that…until it comes time to get a driver’s license or pay your taxes. On a day-by-day basis, it doesn’t matter what you call yourself. Maybe you spend more time in Virginia than you do in Maryland–that’s perfectly fine, but it doesn’t make you a citizen there.
When it comes to state citizenship, all that matters is “where do you live?” Your state depends upon which side of the state line you actually reside, regardless of anything else. It’s the same with parish membership. Parishes have geographic boundaries, and one’s “proper parish” (that is, one’s parish of membership) is the one in whose boundaries you live. Nothing else matters.
You can go to Mass in another parish, and you’re most welcome to do so; just as you can go shopping or spend your leisure time in a neighboring state as much as you like.
Here’s a good example of parish boundaries. And I mean this ONLY by way of example
That’s the Archdiocese of Philadelphia webpage. Click on a few parishes at random, and you’ll see very specific parish boundaries.
In recent years, the Archdiocese has found it necessary to enforce parish boundaries very closely. This has to do with parish closings/consolidating and the diocese history where so many people were in previous ethnic parishes (personal parishes) and were scattered all over the territory.
For years people said “it doesn’t matter” or “I’ll do as I please” (often the advice given here on these forums, mind you). The Archdiocese realized that this had become a problem, and had to fix it. Those people who said “I’ll just do as I please” are now very surprised when they need to go to their proper parish, they go to the wrong parish and make “demands” of the pastor, only to be told that they have to go to their own parish. They say things like “I’ve been registered here for years” or “I’ve been going to Mass here for years” but that doesn’t change things because they’re not approaching their own proper parish.
Could something similar happen in another diocese? Very likely. It is happening right now in other places, especially those places that in the past enjoyed a large number of local parishes, where people used to have “options” to go to one of several.
The simple fact is that parish membership depends upon where you live. People on these forums will quickly advise you “it doesn’t matter, just do as you please” But consider this:
when the time comes that you have some problem or difficulty because you decided to heed their advice and just “do as you please” where will those people be?
Can these posters guarantee you that registering yourself or considering yourself a member of a parish other-than-your-own will not be a problem in the future? Will they be there to make things right when you do encounter a problem? Can you appeal a bishop’s decision to the posters on CAF?
Something to think about.