Let me try to explain my “schism” definition again. The schisms are here on earth, but not on the spiritual plane. From all the schisms over the years (and sub-schisms from those), the theological definition of God has not changed as many times as schisms occurred because that is what is agreed upon.
The OP asked about an instance on when a non-Catholic would choose to go to Catholic confession, that means something else is drawing them to go a priest as an intermediary, when as you say they usually try to go the direct route. In the end it is an instance by instance situation when it would happen in real life. Each non-Catholic would have their own reasons to do this. Yet I would think that forgiveness would still happen, it may not fit the “official” definition, but something will happen as the priest gives his blessing, what that causes the non-Catholic to do is an individual situation to each non-Catholic.
“Heresy” has always created more divisions than healing them. All posters on this board are more alike than not if you look at the whole person and away from the anonymity of the internet. If you look at humanity as a whole “liberal vs conservative”, “orthodox vs heterodox” seems very minor in the big picture of life and can come across as internal distortions of humanity.
“Relativism” is defined as:
a theory that knowledge is relative to the limited nature of the mind and the conditions of knowing (From
M-W.com)
This is everything in life, as my previous examples (5th Luminous Mystery Discussion, actual mechanism of confession), we are limited by our human minds and conditions of knowing all. The Church (actually all institutions, religious or not) all have this weakness which due to our humanity cannot be totally overcome.
It is good to be aware of our weaknesses, both as part of humanity as a whole and each of us personally. Yet our weaknesses can be turned into strengths if we are aware of them (e.g. in job interviews). I just saw today that a Cardinal from Quebec is putting his own weaknesses into the public eye, a very noble stance.