The priest was greeting people after Mass and one parishioner came to him with a question: "Father, why do you keep saying 'go to confession' in your homilies when everyone there in the mass is already doing so?" The priest asked, "I'm sorry, but what do you mean?" "We all say the 'confession of sin' in every mass, so what need is there for us to go to confession again?" the parishioner responded. "Whoa! you have made a mistake; the confession of sin in the Mass only covers venial sins but not grave sins. The Church assumes that everyone has gone to the sacrament of confession outside of Mass, and has likely only committed venial sins since that time, and then the confession that we recite together only covers those venial sins" said Father. The parishioner, as you might expect, said, "What!!!?"
I do not know exactly how many people actually have this opinion; I could only guess. The fact, however, that I have had discussions very much like the one above, tells me that there are likely many others with the same mistaken perspective. Although I assume that all priests are taught about this crucial distinction, with the drastically low numbers of laity coming to confession, there is clearly something that is making them think that they are "OK" with God in spite of this. What could be leading in this direction? I certainly do not think that this is the only reason, but there is one thing that might be contributing to it. In fact, this one statement can easily be misunderstood (particularly by people who are looking for a reason not to go to the sacrament of confession).
The Roman Missal introduction to the penitential rite says "let us confess our sins and so prepare ourselves for the sacred mysteries." Consider this statement with me for a moment, especially as it is being stated to large numbers of the faithful who have a very poor understanding of the Catholic faith. Taken out of context from the whole of Catholic theology, this could possibly make someone think that this is all the preparation they need; especially if they do not have a good grounding in the church's teachings on sin.
The Divine Worship Mass (which I use in my Ordinariate parish) is more specific, but still makes no clear distinction between grave and venial sin: "You who are in love and charity with your neighbor and intend to lead a new life, following the commandments of God, and walking from henceforth in His holy ways, draw near with faith, and make your humble confession to Almighty God, meekly kneeling upon your knees." I am not faulting either the Divine Worship Mass, nor the Roman Missal, just stating how they can be misunderstood in today's context. It is possible that someone could come into the Divine Worship form of the Mass as well, thinking that the corporate confession of faith and declaration of forgiveness that follows both apply fully to grave sins. I am not advocating tinkering with the specific wording of the Mass (please do not assume that!). That will not truly solve the issue. Something deeper must be done.
What we need is first off a heavy dose of humility and secondly, a deeper understanding of sin. With these two things in our hearts we will be able to return to the proper practice of the sacrament of confession. Today there are many ways that people seek to avoid the sacrament of confession. Making excuses or simply ignoring it might well be the most common means, but for those who genuinely believe that the confession during Mass actually covers grave sin, I will at least give them credit for attempting to do something about their sin. The problem, however, is that this latter method is akin to taking a pain-reliever to overcome an allergy attack -- it is not intended for it, and will not have any effect.
As the Scriptures tell us many times, we cannot run from our sins. Adam and Eve tried it, and their son Cain took after them. So do we all try to avoid dealing with our sins. Yet, Christ's grace and forgiveness is so great that we should never think that we have a better method of dealing with sin. The Church's "bare minimum" of once-a-year confession is a rarity for most. I regularly encourage my parishioners to go to confession, so I will say it again. Do not come up with excuses; and make sure that you understand the Church's teachings in regard to our sins (we are dealing, of course, with your eternal destiny). Christ is waiting for you in the confessional, and He loves to give you His grace.