I think it is always distressing to witness an example of liturgical abuse, regardless of how serious the situation is; it's even more distressing to feel as though nothing ever gets done, that one's protests are ineffective or one's questions go unanswered, and that in general the average priest, pastor, or bishop takes liturgical abuse far less seriously than lay people do.
I'm not sure that is actually true, however. Certainly there are some clergy members, from priests to bishops, who are indifferent to liturgical abuse or who celebrate the Holy Sacrifice indifferently and irregularly themselves. But is this the case in the majority of situations? Even if it was so in the not-so-distant past, is it still so now? And will it be so in the future, once the new translation of the Mass in English is implemented (and with it, the opportunity--carpe diem!--for pastors to improve many things they've probably left alone till now)?
I think that what happens sometimes is that a parishioner sees some irregularity, confronts the erring priest directly or his pastor about it, gets a lot of push-back or stonewalling, and marches away in disgust, believing that priests just don't get it, and don't really care whether or not the Mass is celebrated reverently or by the book. Sometimes, though, this seeming lack of caring comes from the way the matter is approached, the timing, the seriousness of the complaint, and many other things that have nothing to do with whether the priest in question cares about liturgical abuse.
Father Z. has a permanent link to a post he wrote detailing how to write to the Vatican, to bishops, etc. While this is helpful, I think that it might be a good idea to consider the more general question: what should we do when we witness liturgical abuse? My ideas here are not particularly original, but I've used them myself, and share them for what they're worth:
1. Determine whether what you saw was, in fact, an abuse. It's amazing how easy it is to miss this step. I myself was composing letters in my head on the way home from Mass one Sunday before I got home. Then I looked up the thing I'd seen happen, and found out it was a new directive coming from Rome clarifying a rubric that had been unclear before. There are various optional liturgical actions etc. that priests might have for various Sundays or feast days, and rushing to complain before finding out whether anything out of line actually occurred only makes a person look like a chronic complainer--who will henceforth be ignored.
2. Try to gauge the seriousness of the abuse. Sometimes that is easily done, in the more obvious cases, when a priest is playing fast-and-loose with the rubrics, or is making up the whole rite, or both. Other times, though, it isn't; what seems like an outrageous violation of the Holy Sacrifice may be relatively small. When in doubt, talk to other Catholics about it and see what they think, or do a little research to find out if the incident is something that anyone could easily see is not permitted, or if there is a bit of uncertainty about it. One important note: bear in mind that some "abuse" is merely a momentary lapse on the part of the celebrant; I've known priests, for example, who say daily Masses so often that they honestly forget the Creed at the first Mass on Sunday, and launch straight into the prayers of the faithful. Never call "abuse" what might be accident or honest mistake.
3. Find out whether the abuse is a regular occurrence or a one-time mishap. Serious one-time mishaps ought to be dealt with anyway, but it makes a difference whether we can say, "Father Smith always omits the Creed on Sundays," or whether it is only true to say, "Sometimes Father Smith omits the Creed when he is rushing to get to the hospital chapel for their Mass which follows ours a bit too closely."
4. Make sure you know who is responsible for the abuse. Did you see a lector or EMHC behaving in a way that violates the rubrics? Was it a deacon? Was it a priest--and if so, a regular priest, a "frequent" visiting priest, or a visiting priest you've never seen before? Was it the pastor, or is the abuse clearly taking place under his direction? Or did a lay person not assisting in some specific area do something untoward?
5. Give the pastor both time and your trust that he will take care of things. Only if you know for certain he won't should you proceed further; it is the job of the pastor to make sure the liturgy is being conducted correctly in his parish, and if he tells you that the matter you're concerned about isn't anything to worry about and won't happen again, take him at his word.
Once you've determined those things, you have to decide your best course of action. If the abuse is relatively small, has only happened once, and was committed by a deacon or assistant, you may want to find time to speak to the pastor about it. Never do this on a Sunday, especially not the Sunday when the abuse occurred and your emotions might cause you to take a tone that won't be appreciated. Pastors are really busy on Sundays. They don't have time to worry about what Father Smith just did at the 10:00 Mass when they are preparing for the 11:30. Ask the parish secretary when a good time to call or visit Father might be, or leave a message asking him to call at his convenience.
If the abuse involves the pastor, or is frequent and regular, or is terribly serious, I would suggest writing an actual, real letter (not an email, even if the pastor is relatively tech-savvy). Keep in mind Fr. Z's tips on writing, and if you are writing about something the pastor did, write to the bishop of the diocese, and carbon-copy the pastor and the diocesan vicar of priests (if possible).
Here is a sample letter, using an example from my blog comments (and I hope the commenter doesn't mind!):
Address of writer
City, State, Zip
The Rev. Thischurch Pastor
St. Michael the Archangel Catholic Church
Address of parish
City, State, Zip
Dear Rev. Pastor:
Let me begin by saying how truly blessed I am to be a member of St. Michael's parish! Your attentive care to all the souls here, the concern you and all our priests have for the Mass and the sacraments, and the obvious signs of faithfulness and fidelity to the Church among the congregation are a joy to experience.
I am particularly grateful to Ms. Slightly Nutty for her work with our parish teens, and to Father Youngatheart for celebrating the Youth Mass once a month. Their dedication is inspiring, and their obvious love for the youth of the parish serves as a good example to all of us.
However, it is my understanding that the teens' practice of acting out the Gospel instead of having Father read it, as required in the General Instruction of the Roman Missal (GIRM 133-134), is not permitted in the liturgy. While their enthusiasm while doing so is palpable and sincere, it would seem that this practice is not consistent with the mind of the Church as to the proper way of reading the Gospel at Mass. Perhaps some time could be made for the teens to present their skits or performances immediately following Mass in the parish hall as coffee and doughnuts are being served?
Respectfully yours, etc.
Now, I'm sure some people will say that they've written letters exactly like the above to no avail. That's where you have to know what to do if the letter is ignored and the abuse continued:
1. Write a second letter. Refer to the first letter. Carbon copy the second letter to the diocesan office of liturgy and worship, or to the vicar of priests or vicar general, or some combination of these people.
2. If there is no response there, write a third letter to the bishop, copying everybody you've contacted so far.
3. Still no response: contact the appropriate Vatican office (again, copy everybody). Be prepared to wait a long time before hearing back.
Obviously, if a matter is going to get to number three above, it's going to have to be serious. Writing to a Vatican office (or even to one's bishop) because Father Smith skipped the Creed one time on Sunday, April 4, 2011, and he might have done so because a toddler fell out of a front pew and bruised his forehead right as Father was about to stand up after the pause between the homily and the Creed (but you're still really mad about it) isn't going to look all that good to the eventual person who has to read your letter.
Some people will read the above, shake their heads, and say, "It's just too much trouble. Why should I have to do any of this?" But if we're going to complain about serious liturgical abuses, we owe it to our pastors and bishops to be willing to do what it takes to bring these matters to their attention. They can't be everywhere, at every parish Mass; if we witness something truly offensive to Our Lord the least we ought to be willing to do is write and mail a few letters.