Informing people of a sin that you made them do

Question

Is there any obligation to inform someone of a sin that came about because of you, which they will never realise unless you reveal it, and it is already too late (and won't be repeated by not informing)?

For example, if one had guests and accidentally served a milky dessert after a meaty meal, Chas veshalom.

---

Points that would be good to address:

• Perhaps the answer differs if it was, from their point of view, b'ones (they were compelled e.g. the dessert wasn't detectably milky) or b'shogeg (they share some blame due to their negligence e.g. if one served the dessert in the packaging and anyone had an opportunity to look at the label, but they didn't)?

• What about if it was d'oraita (Torah prohibition e.g. served them treif meat) vs d'rabbanan (Rabbinic prohibition e.g. served them chicken in a milky sauce).

• Will the answer differ if there is a reputational damage at stake? E.g. they or others will refuse to eat by you in future.

Answer 1

The rabbis did not want to look too closely at the lineage of people. In Kiddushin 71b, Ulla said : [You are worried about finding a wife with good lineage for your son?] Do we know where we come from? Can we be sure that our lineage is unflawed? Perhaps we are from those about whom it is written: “They have ravished the women in Zion, the maidens in the cities of Judah” (Lamentations 5:11). Another rabbi (ref?) said he could spot mamzerim on sight, but would say nothing, especially because some gedolei Yisrael were among them. Point: Don't stir the pot if no good can come out of doing so. Let sleeping dogs lie. If the person you wronged does not recognize by himself you did so and suffered no harm, you are under no obligation to confess to him.