Hosting Non Religious / Safek Jews
If it is poskined that someone is a sofek Jew (karov livadai) and they are not Shomer Shabbos must you tell their Shabbos hosts that this person may not be Jewish, or that they are not Shomer Shabbos, to insure that their wine is not touched by a possible goy, or a non Shomer Shabbos person? Is the responsibility of the hosts to insure their wine is mevushal, or must I who am sending them guests tell them?
a kiruv worker
Many religious families are aware of the various pertinent halachos when having non religious guests. However, there are certainly some who are not aware of some basic halachos. Based on your judgement it would certainly be a good idea to educate any hosts who are ignorant of these halachos. One who is a safek Jew, once they are “observant” [acting and dressing as a religious Jew] and have not yet undergone geirus, there would be no way for even a knowledgeable person to know to be aware. In such a situation the host should be informed by someone of the situation.