Ping!
Haven’t they been regularized already? If not - thank you for posting this. Good info to have.
This is interesting. I would not have thought of it’s being an issue, because the SSPX priests are validly ordained. The point about “simulating a sacrament” makes sense, if the penitent knows that a valid absolution requires diocesan faculties, and knows a SSPX priest doesn’t have faculties, then clearly there’s a sense of defiance, just as if a person who wasn’t free to marry went through a marriage ceremony.
On the other hand, one could confess to a layperson, simply as a pious exercise in penitence, and that wouldn’t bring this area of canon law up at all.