dotCommonweal notes this story on no phone-in or internet confessions for Coptic Christians. I noted the given reason in the press:
Confessions over the telephone are forbidden, because there is a chance the telephones are monitored and the confessions will reach state security.
A confession over the Internet does not count as a confession, because everybody can look at it and it won’t be secret.
I hope there was more.
Privacy is indeed important, but the Roman reasoning has stated that a sacrament requires a physical presence of celebrants: minister and recipient both. That trumps another value, privacy. Privacy, of course, remains gravely important.
If a person were to overhear a confession that would not invalidate the sacrament. If accidental, it would be unfortunate. If intentional, gravely sinful. But still the sacrament would remain valid.