Recently I was reading books by and about Charlotte Bronte, the famous 19th century British novelist who wrote Jane Eyre and Villete, among other classics.
In one of her books it talks about a Protestant character going into a confession booth, but who ultimately tells the priest, before confessing, that she is not Catholic, but evangelical; and so the priest tells her that he cannot give her the sacrament, as she is not formally part of the Church. In Charlotte Bronte’s own lifetime, Charlotte, out of curiosity it would seem, went to a confession booth, but ultimately did not confess before the priest since she didn’t know the formula to confession.
Anyhow, my question is: say an evangelical, Mormon, etc. does infiltrate the confession box undetected as a non-Catholic. If the person goes through confession, does that person, after confessing, walk away from the church free from the mortal sin that he or she walked in with?