Father Z posts what he calls a “rant” and it is on the topic of face-to-face confession. He mentions this from Church law:
§ 3: Confessions are not to be heard outside the confessional without a just cause.
Whether the cause is “just” is presumably determined by the priest.
Dealing with mental illness as I do (Bipolar Disorder and Asperger Syndrome) I always have face-to-face confession.
Man’s imperfection is such that there are many things that the Church did not understand a thousand years ago that are understood better today, and there are things that the Church does not understand now that the Church will understand better a thousand years from now. Dealing with mental illness is one of those things still not quite understood. Some things, like the male priesthood, will not ever change. The rules about the confessional, though, are disciplines, not doctrines, and such things can change or, at least, be “tweaked” to fit better with our growth in understanding of things like mental illness.
If the cause is “just” for face-to-face confession, then in such a circumstance, whatever it may be, the face-to-face confession is actually better than one in the traditional confessional.
Father Z makes an excellent point here:
The grate was included in confessionals for a reason: it keeps both people apart. Priests must be protected from accusations.
I would say that confessions should generally take place where the grate is between, but there are certainly just causes for face-to-face confession.